It seems that what you consider to be extreme are actually not that bad at all. Perhaps your lack of time for a girlfriend has turned your direction of sexual exertion into pornography--which is, by all means, pretty normal.

I wouldn't worry about it. Remember, you're 21, which is considerably young. Once you finish your degree and get a job, start a business, or whatever it is you plan on doing, then you can worry about it. Shit, maybe you can meet somebody later in college...