My phone is just really screwed up lol

I got this phone in late December of 2015, I dropped it around December of 2016. It cracked after I dropped it, but isn't cracked too severely.

Today though after I pulled it out of my pocket, part of the screen was blacked out (picture attached) and there are colored bars going across the screen. I don't think I did anything to it. I haven't dropped it recently and I don't think I got it wet at all. I've asked around, and people have said that either the back light partially went out or some pixels died. Both of those involve getting my screen replaced, but unfortunately I'm broke so I can't do that.

Also, my phone charges very quickly but the battery runs down even faster, and I want that fixed too. Help!