OK EVERYONE I FOUND OUT WHAT HAPPENED. It turns out that my timing belt tensioner spring went. I hinted on this because I figured out that the terrible noise (which turned out to be the loose tensioner rattling around) disappeared at higher revs. I also inspected the timing belt again and though it seemed to be tight at first, loosened up quite a bit when i pushed on it and didn't spring back. I don't know how I missed this before lol. So anyways took the top plastic timing belt cover off to get a better look at the belt and sure enough, the spring was not attached to the peg. Then, I took the timing belt off and turns out the bearing on the tensioner and the idler are toast and of course the spring is stretched and wrecked. As for the bad running, I'm guessing the belt may have skipped a tooth or two because the tensioner was toast and the belt came loose. It's funny how coincidental it is that the spring went right after I took the valve cover off lol. Anyways I guess that shows how much havoc a 3$ part causes. Thanks for everyone's help!
PS. Does anybody know of good, fairly cheap replacement tensioners and idlers?