Naming Trouble

My boyfriend and I can not agree on names. I threw out the name Declan a few weeks ago when we believed we were having a girl but unsure. Yesterday, I accidentally saw my baby’s gender at the ultrasound and SURPRISE it’s a boy (which is what I was hoping for) but all of the sudden he HATES the name. I feel like this baby’s name is Declan. It feels right and i love how it rings with my other sons name (Emett and Declan). I’m literally so upset he is completely against the name. Maybe I’m just being hormonal. No other names are striking interest and feel right. What do I do?!