LONG RANT! Ridiculous "family"

So, my SOs brothers girlfriend of 10 years (yeah, girlfriend.) is ridiculous EVERY TIME one of the "sisters" gets pregnant. (We will call her 1) She demands every ounce of attention anyone else could possibly get. No, I'm not just pregnant and hormonal and assuming, it's happened multiple times. One sister, got pregnant, told her (they were close at the time) and she instantly started trying because of it. Everyone was like oh is a coincidence and let it go of course! She had a couple more kids, then fast forward to two years ago.

Another brothers wife (we will call her 2) got pregnant and somehow she ended up pregnant at the same time AGAIN, but three weeks earlier than 2! Later, we found out that she knew 2 was trying because 2s husband told his brother while they tried. Of course, no one said anything and basically said it's a coincidence, let it be, let her enjoy her moment... again. UNTIL she started literally copying EVERYTHING 2 posted online about baby, (every milestone post, photo, how she was feeling statuses) or even what she did in person (what she bought, how she dressed, every maternity photo pose, EVEN THE COLOR SHE DYED HER HAIR!) not to mention we had to BEG her for belly pictures when she was pregnant alone, had her own moment and didn't wanna show anything off. She even tried to have the baby shower (kid #5, girl #4) on the same day!! So of course 2 was bothered, like anyone else would be!

Fast forward again to when 2 was coming up to her due date-- 1 asked 2 every single day if she was feeling contractions, how she's doing etc. 2 wasn't going to tell her and she caught that. SO 1 asked mom. (Mother in law) and coincidentally, mom was bringing 2 to the hospital that night because she was having contractions and was dilated; 40 weeks +a few days and in active labor-- mom told 1.

A couple hours passed, 1 texts 2 saying how she "didn't feel good" and was going to the hospital and how the "doctors said she could be induced" she did because she knew 2 was in labor. She was 37 weeks at the time. Of course, babies ended up with the same birthday and she milked it HARD! Then got upset when 2 got more attention because it was her first child of course, went to her boyfriend and complained and got the whole family fighting.

Fast forward to now! I am pregnant, 1 is pregnant (8 weeks behind me) AND 2 is pregnant (way far behind me, I don't even know exact) she's been doing it AGAIN this whole pregnancy to both of us. 2 and I are very close, we were close friends beforehand and always wanted to take maternity photos together and pretty much experience it together as a whole! 2, knowing exactly what 1 was doing to me of course confronted the situation, thinking it would stop and I wouldn't have to go through what she already went through once. 1 ran and cried to her SO, rather than accepting we saw what she was doing and fully played victim, got the whole family fighting again. 1 blocked 2 from seeing her online posts, and continued to do what she was doing to both of us, just to me.

Every belly picture I posted, 1 posted right after; every way I worded it, she did it super close and changed a word or two. She simply couldn't have her own pace even being 8 weeks behind me, she acted like we were feeling/growing the same way and all. It really bothered me because this is my first, I enjoy having my own moment and my own memories even if that means the attention isn't on me, I posted for ME and for me to be able to show my child in the future; I'd like it if I could have that at least and not have a shadow with every move I make. (Not to mention shes 10 years older than me, and should be more mature than this.) Especially seeing how this is her 6th and I knew exactly what shes doing. Of course, she saw everyone was giving me the attention because they've all been waiting for it to happen for me, SHE HATED IT. She did it even harder, made it even more obvious but no one saw other than a select few. I let it go and blocked her posts to avoid family drama and stress while pregnant.

Fast forward again to now. I'm almost 35 weeks and she's still at it, at 27 almost 28 weeks. Except now, she's calling out contractions and labor feelings and saying "I feel like it'll happen in September but I'm not stopping it, if it happens it happens " which is my due date. Early September. Of course..

She's fine with endangering her child, having a nicu baby ( which she's had before, why would she want to put herself through that terrifying experience again) JUST to have the attention from the family and everyone else, just to be able to publicly post it for her own good; even if it's not for a good reason. It's sickening to me.

My SO calls me crazy, says it's all in my head, but I've literally watched it happen MULTIPLE TIMES. He expects it to not make me emotional, when I just wanted to enjoy my first pregnancy without someone stepping on my ankles with every move I make to pretend we're at the same pace, to try to take every ounce of happiness i try to have with this pregnancy and make it her own.

Am I insane?! I don't understand how I'm the issue here when shes knowingly doing this to me!? She pretends she doesn't realize it, she acts like it's completely normal and she's doing her own thing; but she's not!! She never goes to any family functions, always an excuse. But I know for a fact shes going to come to my baby shower just to attempt to make it about her.

So far, we've had one function where she was there (it was her SOs birthday) and she saw that the family was looking at my ultrasounds and loving on my tummy because it had been a while since they saw me and I grew; she instantly changed out of her flowy dress, put on a tight shirt to try to show her "bump" and acted like she was in pain or nauseous (after gloating her sickness went away at 13 weeks) every time she saw someone talking to me about my baby or my tummy.

I don't understand how no one else can see what she's doing to me purposely?!?! I truly feel bad for her baby, because she literally sees it as an object rather than a life she should be catering to as she grows it.

Should I just fully block her and take the chances of the family calling me insane and possibly fighting again? I don't know what to do anymore...