I was in gym class this morning and I hit heads with another kid and then fell on the ground right on my ear and I heard a shrill screach. Like an alarm. Ever since I have been having a hard time hearing out of my right ear (the one I fell on.) The only way I could explain it is, it feels like I have water in it but I really don't. I can still hear out of it, its just harder.

What happened? Is it serious or just a bruise?

Hmm, it could be a potentially serious problem. You know how teachers used to warn you about 'clapping' your hands to your ears really fast? Doing so can cause a relatively high-pressured burst of air to hit your eardrum, which could have burst the eardrum if you fell pretty hard, which is what it sounds. Having the 'full of water' feeling could mean that damage has been done either to the eardrum (a punctured eardrum might cause such symptoms due to lesser vibrations being created by sound waves) or to the other mechanisms inside the ear (which is much more unlikely).

My suggestion is that you definitely should schedule an appointment with your family physician - they have tools that can be used to scope out the inside of your eye and take a look at your eardrum. If the eardrum is indeed perforated, the physician will recommend to you the proper course of action - which may range from just letting it heal by itself (if the perforation is small enough) to surgically placing a graft onto the eardrum to help it heal. Whatever the outcome, be sure to leave your ears alone for the time being - don't stick anything in, and be extremely careful while taking showers to prevent any water from getting in.

Good luck with everything!