Parents regularly call me a burden

But he's in a shitty situation and needs help. His parents are so self absorbed that they can't see that. They can only answer with "but what about US?" which is the shittiest response you can give to a suicidal individual. They don't give a fuck about their own lives, what makes you think he cares about yours? If you don't feel like helping them just because they don't care about you, you just revealed your nature as an hypocritical selfish scumbag. At least suicidal people have an excuse and the decency to drop the facade usually.

>I don't buy the "always think positive" nonsense
me neither

well, declining health is mostly a choice, whether or not you can see it. If you can afford shitty food you can afford good food, it's just less convenient and you have to cook properly. But a simple budget "paleo" diet will restore health and is cheap and easy to do.

Meditation/diet/sleep quality is the key to improving your health, research them.. find good sources (robb wolf is a great resource for example)

The money thing may become easier once you've started restoring your health. The body/mind want to be healthy, but they need the right building blocks.. and society is ass-backwards in terms of health recommendations;

grains/soya/vegetable oils/sugar = worst possible things to eat health wise

stay away from those, eat lowish carb or ketogenic (perhaps higher carb if you are doing a lot of glycogen depleting workouts),

eat lots of meat/eggs - saturated/mono-unsaturated fat is all good for you, be careful with any high omega-6 polyunsaturated fats (veg oils - avoid like the plague) - some low glycemic veg is fine if you want, though the importance of plants is highly over-stated especially if you're getting organ meats and lots of eggs in your diet somehow (these are incredible nutrient storehouses).

+ exercise, sorry forgot to say... though I'd argue that exercise usually comes automatically by fixing metabolic problems.. it's still useful to force yourself to make a small habit of exercise in the beginning though. Similar to meditation, it requires some effort before you realise the immense lasting benefit that it gives

We live in the information age, with unprecedented access to permissionless information... take advantage of it. If you're not confident in your critical thinking/reasoning abilities, then that needs to come first, else you will not be able to sort the bad information from the modern/accurate. But you can do it ^

Maybe stop being a piece of shit, grow the fuck up and slowly ease your way into your own life. Take responsibility for your life. It is not your parents job anymore(depending on how old you are). Stop threatening to kill yourself dumbass. Your parents obviously care about you enough to still take care of you. And get a fucking job. No matter what you do for a living, there is nothing like having a paycheck you worked for.