I would stop in since they've asked you and offer your congratulations. I would also take a gift, but something small since you don't know them well. How about a little stuffed yorkie? I just bought one for a friend's daughter's birthday from Target - it come in a little carrier!! That way you are sharing something of you with them, rather than just any old gift!!
Don't be too hard on yourself - we've all had those times when life is poop (the smelly kind)!!! This, too - shall pass!
__________________  Sissy & Angel |