Baby rolling onto stomach in sleep before he’s (I’m?) ready.

I don’t know if this is more of a cry for advice or a cry for support from other parents.

My almost 5-month old baby has started to roll onto his stomach in his sleep. Now, my husband says he’s seen him roll back onto his back but I haven’t yet. His positioning was perfect so he could easily breathe but I couldn’t bring myself to let him stay in that position. My brain keeps screaming danger and now I wake up in a mild panic every time I try to sleep because I’m worried I’ll miss him rolling over and something bad will happen.

I know I’m overreacting but I don’t have a support system in this outside of my husband and I don’t know how to react. Do I need to watch him? Flip him over? Just trust that he knows how to tell when he’s not getting enough air?

Any other parents who have been here, how do I navigate this step?