Guilt, puzzling thing

I've had many people tell me not to feel guilty for some of these things, but that is far easier to say than to do.
I feel guilty if I laugh too much or have too much fun.  It comes in Ebs and Flows.  There are days I feel no guilt at all and other days I'm full of guilt.
Don't get me wrong, I don't feel guilty for anything I have done or not done where Chad is concerned.  I'm at complete peace with that (Thank you Lord), but I do feel guilty that my life continues and I experience things that I know he isn't here to share in or experience himself. 
If I have a moment when I am at complete peace, suddenly I feel guilty.  If I enjoy singing a song in my car while driving, I will suddenly feel guilty.
I can't explain it and there is really nothing anyone can do to make that go away.  It just is what it is.  I seriously doubt that will ever go away and if that's the case, I will just deal with it, but it is a very puzzling thing.