I'd try a pastor or a Christian counselor. Most pastors are very familiar with the trouble people can get themselves into. It's usually hard to shock a pastor. A pastor is well-equipped to help you see that if you're sorry for what you've done, God forgives you. I know you don't feel forgiven, but hearing it from a pastor could help the truth sink in.
Christian counselors are even harder to shock.
A Christian counselor can help you work through some of the deeper issues involved in your sexual identity. Of course, you might not have any deeper issues. You might be able to leave this incident in the past and move on. But it sounds like you'd like some help dealing with your guilt and fear. And if you're struggling with homosexual feelings on a regular basis, a Christian counselor can help you figure out the complexities of sexuality.