She cheated on you correct? For me, I had major stomach issues after I cheated . I couldn't eat, was in the bathroom all the time, my stomach actually hurt. Now I think it's depression.
Guilt is some heavy stuff though - it could be that or depression.
....Understand, that I can't, not be what I am I'm not the milk, and Cheerios in your spoon ~ Avril Lavigne ~ ..."Nobody's Fool"...