In my last paragraph, I said if there was no swelling, soreness or bleeding, then you probably hadn't been raped anally, but you STILL could have been raped........
As o_mogh said, you would KNOW if you had been raped anally.
What I find more disturbing is that you did not mention being drunk, and especially being drunk to the point of blacking out or passing out......but you just don't remember.
You said that when you woke up your pants were off and this person told you it was just oral and YOU WERE AWAKE.........but you have no memory of any of this?
Unless you can tell us that you WERE, in fact, so drunk you don't remember anything about this encounter, I think it is entirely possible you WERE raped with a club drug like GHB, Rohypnol, also known as "roofies," or ketamine, also known as "Special K."
These are date rape drugs that can be easily slipped into a drink, act very quickly, but do not render you unconscious.........just totally unable to resist a sexual assault or to REMEMBER IT. They also leave the body very quickly which makes it very difficult to prove you were drugged. (And date rape drugs work on both men and women, which surprisingly, many people don't realize)
I would definitely get myself checked for STD's and as long as there is no swelling, soreness or bleeding in or around the anus, I would again say it is unlikely you were raped. If you want complete peace of mind, have a 4th generation DUO test done 4 weeks after this encounter.
Please be careful out there.