Need opinions hateful/negative cousin invited herself in our family trip and now I don’t know if I should go

Mandy • 💏2012 🎀👶🏼1/10/14👼🏻+👼🏻+👼🏻+👼🏻2019👼🏻6/30/19,👼🏻5/31/20

Ok so I’m currently 15 weeks 4 days with baby #2 and our rainbow baby after 4 losses in a row like one cycle after another. Anyways every year we’ve always took a beach trip with my family for memorial weekend it’s always me, my husband, our daughter, my parents, my 3 younger siblings, my one sisters hubby and so, and sometimes my little brother brings a friend. We get just enough rooms for everyone to have a room but family’s share a room like me and my hubby and our daughter have a room and my sister and her hubby and son have a room then my parents, my brother and his friend and my youngest sister and her friend if she brings one. This is our last trip before we have the baby and we REALLY need a vacation like bad ladies! We have almost lost this baby so many times I’ve lost count, we are finally starting to calm down and things are finally looking like they could be ok. Well today my parents did a little bbq and my cousin, her 2 kids and her boyfriend showed up. I hate when my cousin comes around cause she is sooooo fake and she’s hateful and ugly to everyone and when she’s around my moms demeanor changes and she’s constantly telling me “Mandy don’t do this don’t do that” or stopping me mid sentence by giving me a glare or telling me why’d I wear that. Just stupid Shit cause she doesn’t want my cousin being hateful to me but then if she does end up being ugly to me my mom goes along with her to fit in she’s like a damn teenager. Anyways anytime my cousin is around I’m on egg shells not knowing what to say or do cause I don’t eat my mom being like why’d you say or do that or worse have my cousin be hateful to me and then my mom bullies me with my cousin. Well today at the cookout my cousin took it upon herself to invite herself on our beach trip but first off we literally have no room for her and second of all it’s gonna be a living hell if she goes! I don’t know what to do now, we’re closing on our new house soon and we really aren’t gonna have the money to do a different trip before the baby’s born but if she goes I’m gonna be under so much stress it’s not even funny. Plus I get pissed cause my cousin along with tearing me down try’s to tear my hubby down and that I won’t stand for. My hubby is a bigger guy he’s always been that way since birth and I mean yea he has a little bit of a belly but a lot of it is he’s big boned and she sits here and tears him down and picks on his weight. I just can’t handle her shit right now and I’m so confused on what to do. My mom says she’ll have my back but I know her she won’t she’ll be up my ass the entire trip telling me not to say things not to look a certain way. Shit today she was like “your so embarrassing your walking around looking like your 9 months pregnant” and I’m only 4 months. I can’t fuckin help it that I started gaining and showing faster with this baby like wtf idk please help

Here’s 2 pics of my belly to show y’all as she said my embarrassing ass stomach

And this was hubby when I was pregnant with our first