(((jenn))) Because you were assaulted!
You need to work through it until it no longer bothers you this way. You don't have to do it now, but eventually, you probably will need to. Many ppl can deny and stuff feelings and thoughts from such a victimization, often through rationalization (like it was partly your fault or you should have...something..) but that rarely solves the problem.
If you really are suffering, the books say healing will be harder and take longer the longer you wait for therapy.
TC