Aww, hun I'm sorry. Don't take this to heart, I don't believe it has anything to do with you. I have a feeling something is wrong like a UTI or something may be hurting. My dog acted like that once when she had an anal gland infection. She was always loving and then one day was not herself at all.
I would see if you can see a vet is this doesn't improve.
No worries, your baby still loves you! It's just too bad they don't have little voices to tell us what's wrong
Keep us posted.