Sleep regression or Mamma's boy?

B.

My little boy is almost 4 months old and just recently started not wanting to nap during the day. So in the evening when I have stuff to do like shower, etc I'll have his daddy hold him and he absolutely freaks out. Crys and screams to the point where he starts almost choking himself. It always happens around the same time too. He'll be fine with his dad holding him until around this time every evening. Then as soon as I take him he calms down. So my question is, is he doing this because he's just really exhausted from not sleeping enough or is it because I'm not in the room with him? Why does he only do this at a certain te every night? Any advice or experience helps! TIA

Oh and he sleeps fine at night, just during the day he dosent want to nap and if he does it's a short nap.