This is a real thing. For the first few months — and really sort of forever — every time you take a shower or a nap or anything without baby physically touching you, you will think you hear him crying.
He probably isn’t.
Even if he is, whatever adult you left him with has him and he is fine. Finish your shower, take your nap. They will come get you if you are acutely needed. (You’re always baseline needed from now on — surprise!)
Part of our Newborn Survival Guide.