I know it's wrong, but I can't stop thinking about when I stole from my friend.
What are you going to do about it?
I don't know. Should I tell my friend?
Yes you should. Being honest is the best policy. Your friend will forgive you.
I have my doubts. Is it okay if I lie?
It is not ok to lie here. Just tell your friend about what you did. It is not worth it to potentially damage the relationship.