You should tell someone. If you don't this will happen again, to someone else. If you are really worried that you won't be taken seriously, you could call the police from a pay phone. That would give you a certain level of anonymity.

Reporting it seems like a good idea. You may be able to assist the police in stopping these guys. You can ask to remain anonymous, even if you aren't up to testifying or anything it could still aid in an investigation.

Being raped by the same sex doesn't mean you have a preference for the same sex. Heck, even if you enjoy sexual acts (consensual or not) it doesn't mean you prefer the gender of the person who performed them on you. Not that there's anything wrong with that, I think homosexuals are awesome (though I don't like them using the 'gay' slang).

Part of feeling dirty is psychological, but it is often rooted in reality, dealing with real things may help. First off, you should go to a hospital and get a rape kit performed. They can take pictures of your injury and collect biological samples. This will assist in filing a police report.

Plus, once that's done, they can help clean you up (literally) and while you're at it, you could get your blood tested for STDs.

If that comes back negative then my guess is you'll feel cleaner. If it comes back positive: well hey at least you're informed and know how to deal and don't have to wonder about the unknown.

Feeling degraded. Well, let's look at the language: did you go down a grade? Is your quality lowered? When we are injured, then we do sort of lose a little quality, however our body (and our emotions/mind) have the capacity to heal in response to injury and stress. So you will recover compared to when you were violated.

Right now you're in distress. Mastering yourself can turn this into 'eustress' and you can learn from this to become a stronger and more capable person. This IS a possibility. If you have difficulty figuring out how or making choices a therapist might be able to help with this (hospital/police network with pros in stuff like that and can help).

You can not only feel as good as your old self, but even better. This is my opinion, it's my hope you can have hope too. Of course, hope is a feeling and often not something we can choose to feel, but being open to the possibility usually increases the chance of it happening.