Husband is scheduled for vasectomy and I'm panicking!

This is my first time posting here. I've been posting on the Mirena IUD forum due to some serious side effects I suffered from that. Because of all that, my husband is scheduled to get a vasectomy next week so that I never have to take hormonal based birth control ever again. But, I'm not sure I'm ready for him to go through with this. We have two children, a 4 yr. old girl and 1 yr. old boy. I really thought I was ready to be done having children. There are many reasons why we shouldn't have any more, the biggest one being my husband is adamant about wanting to be done. I just can't figure out what is behind my reluctance. I actually can't imagine adding another child to the mix. Some days I feel totally overwhelmed with the 2 that I already have. The only thing I've come up with is this: I am terrified I'm going to "lose" my son to his future wife if and when he gets married some day. I know it's crazy to be worried about this now or to even be worried about it at all! I came from a family of 2 girls, had a girl first and frankly wanted another girl so I could avoid this whole issue. I know the fact that I don't have a great relationship with my mother-in-law is connected to this. Every time I see a family with 2 girls, I feel envious. My husband says even if we did have another child and it turned out to be a girl, that still wouldn't fill this "void" that I have. What is wrong with me? I adore my son and know how irrational and crazy it is to be worrying about something that may or may not even happen 25-30 years from now. I supposed it could be because my hormones are still all screwed up! Anyway, are there any moms out there who have felt this way or am I just certifiably crazy? Thanks for any insight. Tweet