2yo struggling at preschool

My newly 2yo has been going to preschool 3x week for about 2 months. We've had a rough time mostly with illnesses keeping him home almost half the time.

The issue is that when hes there, he refuses to engage with the other kids. He screams and cries if left with the kids to play. He constantly says 'bed bed' because he wants to be left alone in one of the travel cribs they use for naps. He spends most of the day there.

This is not normal for him. At home, he's a normal 2yo, into everything, running, singing, playing with his toys.

I have no issues at pick up or drop off. He walks in on his own without a fuss. But the teachers are saying he immediately wants to go inside to the nap area to lay in one of the beds with his blanket.

It's breaking my heart to think he's just in a tiny travel crib all day alone. Is this just a weird adjustment issue that will resolve itself ? Any thoughts on how to help him?