Annoyed at DH

So DH is best man in a wedding the 23rd I'm due the 31st. No big deal. I may or may not go. And the bride and groom know this. 
My problem is that I've been having contractions on and off and have had to go to the hospital once already. Well this weekend is the bachelor party. They are going four hours away to a casino. I'm cool with it. I've got family here if something were to happen. 
BUT he then proceeds to tell me that he is planning on taking our car (we currently only have one because the other is down for repairs) this weekend. When I mentioned to him that I did not feel comfortable with this. For one thing I have to work and for another we have two children already, and if something unforeseen were to happen or if I were to go into labor I would not have a way to get to a hospital. 
He looked at me like I was crazy, and then laughed and said "okay". 
Am I being unreasonable?
His mom is watching the boys on Sunday while I'm at work and she could take me but I hate having to rely on someone else. Plus we don't always get along and our relationship is a little awkward because of it. 
I'm thankful she's watching the boys on Sunday but I don't want her to have to take me and bring me home from work. 
Am I being hormonal or is he being a little thoughtless?