I need help in the worst way!

I have been thru this and I have bad news for you, what you saw will be with you for a long time and you probably won't get thru it without help. Seek professional help that specializes in what happened to you. Just a side note, try to imagine him looking down at you from where ever he is, smiling, apologizing for what you saw and saying that if you can let it go and move on with your life, he will fell much better and thank you for being his friend.