I have no idea

For the last couple nights off and on my Lo has woken up in the middle of the night hysterical! She is screaming and inconsolable for at least 5-10 mins. I pick her up, try to soothe her but it takes a min to get her to calm down. I have no idea what's wrong. She just turned 7 months today.After about 10 mins she starts to calm and I feed her and she goes back to sleep. It scares me though how hard she's crying when she first wakes. We are co sleeping so I don't think it's separation anxiety. If anyone has any ideas I would appreciate it!