New Years plans making me sad.😞

I just need to rant for a moment because I feel very alone and misunderstood right now. My SO and I are young parents, we have been together since Feb 2013 and this is our first child. I am 18 and he is 21. He wants to go to a party on New Year's eve instead of having a small party at our own place. Personally being young I don't want to be 30 weeks pregnant seen at a party but I want to be able to spend New Years with my SO. I hate staying over night anywhere but my own house because I fall asleep early and sleep in my comfortable pjs (underwear and a t-shirt without a bra) because I can't fall asleep any other way. My SO doesn't understand that and is more than willing to just up and leave me to go to a party and doesn't think twice about spending it with me. Am I just being emotional or reasonable?