I understand your frustration. What helps me get a clearer mind in these situations is stepping back and doing something else for a little while, even perhaps for a few days. Try to clear your mind from fishkeeping and come back with fresh energy. Once you've relaxed your mind a bit, here are some suggestions to help fix the problems:
1. I wouldn't recommend power feeding since you are low on de-chlorinator. I assume you have sizeable specimens; if so, you can back off feeding for a few days, especially if you've been feeding them daily or every other day. If you have smaller specimens, I would feed them every other day or every two days. If you're worried about specific fish not eating, target feed them, but otherwise, back off feeding for a few days to prevent more problems.
2. Try to exert some self-control when buying and selling new fish. Trust me, I've been there. Some of the fish are native species; you collected them, correct? Perhaps take the ones you don't care as much for, put them back where they came from (as long as they are healthy and all of that), and then keep the ones that are your absolute favorites. You have to have some self-control when getting fish. I know it's hard, considering there are 100s of beautiful and awesome species of freshwater fish, but it's a key component of this hobby (and honestly any hobby for that matter). Also, for the sharks and other fish that are getting too large, again, if they're native, put them back where they came from; if not, perhaps sell/give them on Craigslist or Facebook Marketplace.
3. Research, Research, Research! On the same line as above, do a ton of research to prevent random impulse buys every time you go to the fish store, lake, or wherever you get your fish. Once I knew about most species around my area's fish stores (especially oddballs that were the coolest fish), it helped me to reason when the temptation of rare new fish appeared so that I could bite my wallet, move on, and dream of having the proper housing for the fish later on.
4. Regarding the plants, I can't help you there. I'm horrible with aquatic plants, lol.
Finally, 5. Don't be mad at your siblings or parents. Those circumstances are out of your control; they aren't your fault either. They are just circumstances that are out of your control. Instead, perhaps research some ways you can make money online. You could do plenty of things that are suitable for your age. Start a YouTube channel or be an online graphic designer if you're good at graphic design. Or, if you're good at writing, be a writer for various businesses. There are many ways to make money; you just have to find them.
I hope this helps, and I wish you the best of luck.
