I'm so sorry your friend put you in this position. There is no need for you to feel guilty. You can only do what you can do. Too, lending money to a friend is a sure way to lose one, at least that is what my mother always told me. Anyway, just give it time but take care of yourself. Do you have another friend that you can talk to about the situation? Maybe sharing the story will help you to alleviate the symptoms. I hope you let yourself off of the hook soon, as you don't deserve to feel bad about it.