Should I be mad?

Jessica
I'm 7 months pregnant and my boyfriend is leaving to Vegas with a few of his friends. I want to be happy for him but it kinda makes me feels unimportant. Im not sure how I should feel right now, but I know I'm not happy he went. 
I also feel very alone in my pregnancy. I almost feel like when my baby comes, mentally I'll be "checked out" from him. I honestly feel that when my baby comes, I'll just had a mindset of "ok NOW you want to be here with me? Where were you when I was pregnant?" 
Also! My birthday is nov 14. And he's using his sick time to go to vegas instead of my birthday. He says he's trying to find a switch but nov 14 lands on a Monday. No one likes working on a Monday. It just really really upsets me. 
He's technically supposed to work the weekend of going to Vegas but he's calling off and using sick time. But says he's finding a switch for my birthday. Not sure why it's ok to call off for Vegas and not my birthday.