A little while ago I started having trouble with my toilet when flushing. It's flushing too much water, leaving little left in the bowl. It also makes loud noises at the end of the flush.
There's still some water left in the tank, so when I flush it very carefully a second time I can get it to fill up just enough.
I'm in an apartment on the first floor (second if you're from the US), in case that matters.
What could be causing this?
Here's a picture of the tank: