feeling left out and emotional

I just want to vent. maybe I'm being over emotional and hormonal? I don't know but I hate feeling left out.

back story ... I am 25 and we have very few friends and definitely no friends who are also married let alone expecting or have kids. I am almost 38 weeks along. my husband has an identical twin and they have a best friend who is getting married in November. I have known this best friend for over a decade, as long as I've known the twins and he was a groomsman at my wedding and they will be groomsmen at his. i have met the fiance a few times and she seems great, very friendly. also, my husbands twin has a girlfriend, who is... just AWFUL. we all dislike her for so many reasons. just immature and frankly, annoying as hell. as far as I know she isn't extremely close with this new fiance, just as friendly as I am with her.

so. the story is the groom to be is having a bachelor party on a cruise around Halloween weekend and of course the twins are going. when I found out I was pregnant we were about to go on a cruise (me, the twins and the girlfriend) but had to cancel due to Zika virus and we all got credit back for a future cruise which the boys are now using for this bachelor party cruise.

I just found out this girl,. the fiance, is having a bachelorette party on a cruise the same weekend. she invited my husband twins girlfriend and she is using her credit for it as well. I knew nothing about it as I am not invited at all.

now I am very upset. I'm thinking a few things.... does she not like me? does she think I will just say no because I will have a baby? if so why not invite me as a courtesy? she obviously knows I have the credit so maybe she thinks I will say yes and doesn't want me there so she didn't invite me? they must have spoken about it and decided not to. is this what it will be like? worse once the baby comes...? why is it bothering me so much? why invite the other girl and not me? I am just very emotional and not sure if this is even a big deal but feeling soo left out and hurt. my husband is saying he won't go either which makes me feel guilty and even worse. I told him to just forget about it but I kind of want to know why or what I did wrong or what the hell. idk. I feel silly. ugh.

how do I make friends who are like me?