Hey! Not sure if anyone's still here, but here's a serious answer:
TL;DR: everyone perceives swear words differently, and swearing can be used for purposes other than to insult someone directly
Swear words serve a purpose in language just like every other word. People, or at least many English speaking people that I've encountered, tend to consider rude language/swearing to be superfluous speech, words that can and in some cases should, be removed from the language. That's a misconception. The point and purpose of swear words is to be taboo and rude. If these words didn't exist, they would likely be substituted by something else, because from a sociolinguistic perspective, our society right now has evolved to need a linguistic way to express the things that are conveyed with swearing, even if it's really bad things like racism, disdain, threats of violence.
Now, one of the interesting things about swear words and rude language in general is that everyone perceives these words with a different severity. Some people feel comfortable with saying "cunt" for one reason or another. For example, Australian and British English speakers tend to be more comfortable with that word than American English speakers. For other people, even minced oaths can be considered rude, such as saying "darn" instead of "damn" or "fiddlesticks" instead of "fuck". It could also have to do with background or identity, like women calling each other "bitch" can be considered less severe than a man calling a woman a "bitch". Or someone who's deeply religious could object to the use of "hell" while someone who isn't might not even consider it rude.
Lets get back to the purpose of swearing. Swearing can have many different uses, such as showing you're part of an in group. Imagine a group of women working in a auto body shop together for example. In order to signal to each other that they're comfortable around each other, they might refer to each other as their "bitches". But that doesn't mean that a customer can come in and say "hey bitch I need new headlights": they're not part of the group, they haven't earned that privilege. Swearing is also a rite of passage. Adults get to swear, but we consider a sign of a good upbringing in the English speaking world as a child that does not swear. Throughout all these uses, there's a through line of flaunting social expectations. Swearing can be used to damage and berate and humiliate, of course, but a lot of swearing is done with subtext. "Hey, you're my friend, this is a relaxed environment, of course you're not going to think when I say a rude word that I'm insulting you" or "I'm feeling such a strong emotion right now that the only words that fit that are very rude".
I also think that as our society moves away from more structured and rigid social roles, swearing is getting more acceptable since we in general are more tolerant of deviations from the norm.
Edit: I've obviously only scratched the surface, since this is a broad and complex topic.
Hope my answer doesn't get buried and I hope you don't feel too overwhelmed by all the responses you're getting. But something I found really useful is frozen veg. If you're struggling to plan healthier meals that are higher calorie, frozen veg is a game changer. It doesn't go bad, it's cheaper than the fresh stuff, and the most important thing is you can add it to your existing diet. I have a soft spot for ramen and box mac and cheese for example, and it's so easy just to throw handfuls of whatever I've got in the freezer into a pot of pasta or ramen to make it just a bit healthier. Hell, you can even forget the ramen altogether and just use the soup base (it's just stock!) to make lazy soup. Add a chopped onion if you're feeling fancy and that's that.
You also list a lot of protein sources that you can't afford to add to your diet. Protein is a necessary nutrient, but it's not the end all to a healthy diet. I say that as a lifelong athlete. It's very easy to get an appropriate amount of protein from plant based sources, and they tend to be a lot cheaper. Plus, they tend to be higher in other macros and nutrients. Soy milk, for example, has the same protein content as dairy milk (but might be more expensive depending on your area). Beans and other legumes are fantastic and tasty. Chickpeas are my favourite. If you have a blender or food processor, you can make hummus very easily. Lentils are also amazing if you are able to cook. Cheap as hell if you buy them in bulk and insanely filling. Indian dhaal is a lentil stew that's fairly easy to make and very tasty. If you can afford it, snack on nuts and seeds. Add peanut butter (look at labels to find some that doesn't have sugar in it) to your diet. Both those things are higher in calorie while also being high in nutrients. If you eat rice, try getting brown rice instead of white rice. It's higher in protein and fiber and will likely keep you full for longer. Potatoes and other root vegetables are also awesome. Versatile, cheap, relatively high calorie, easy to cook, and keep for a long time if stored properly. I like to make a huge pot of potato stew with beans and frozen vegetables and keep it in the fridge for easy meals for like a week. If you're looking for animal protein, check your local grocery for frozen fish. Its usually half the price of the fresh stuff.
I'm not your doctor, but personally, 800-1000 cal/day was terrible for my health. Yeah, it'll make you lose weight, but for me it made me really lethargic and gave me brain fog. It just wasn't enough to keep my body going. Maybe try slowly lowering your calorie intake and see how your body feels. I've also found that in the past, calorie counting was actually counterproductive to my health because what ended up happening was it became a "game" to eat fewer and fewer calories a day. Luckily I saw that and stopped counting calories before it turned into an eating disorder. My point here is just that it'll take some work figuring out what works for you and don't get discouraged if a method doesn't fit your body or your lifestyle.
In terms of exercise, I know it's not a satisfying answer, but it's really going to depend on your body and what type of exercise you're doing. If you're exercising, you should definitely be eating more than 800-1000 cal/day unless you're like, a toddler. It's dangerous in my non-professional opinion to exercise when you're under eating by that amount particularly if you're lifting weights or doing high impact cardio.
I wish you luck on your journey and I hope it all works out for you :)