Super irritable little one

My LO is 16w and all day today has been SUPER irritable. She cries every time she eats, she won’t nap like normal, and she is just really unhappy today. She’s not acting sick, no fever, she’s pooped so I don’t think it’s a belly ache. She’s drooling a lot and chewing on her hands but she’s been doing that for a couple weeks now and no more than normal. I don’t know I’m just confused because she’s normally so chill and has never acted like this before.