baby won't eat

Erin • Mama to 3 beautiful girls
Alright, so I gave my newborn a pacifier while we were at the store. (She used me as a human pacifier all night.) so she had it for 2 hours tops. 
She also has gas now too. She is currently sucking on her thumb and hasn't eaten for 5 hours. I have tried feeding her (we are breastfeeding) but she won't latch. 
I don't know if it's because of nipple confusion (can that happen after 2 hours?) 
Or is it because she has a tummy ache?
 
What do I do???