Am I over reacting

I love my husband, but I can't stand two of his 3 sisters. They are the kind of people who act like they are such humble, kind people, but behind people's back, they gossip and bitch a and thrive off other's misfortune. For about 4 years, I bent over backwards trying to fit in and do everything they wanted me to do...until one of them suggested my husband and I get married overseas so everyone could go on a holiday. When we decided to do that, they spent the rest of the time up to the wedding backstabbing us about how we were so inconsiderate to make it so expensive for everyone. They nominated themselves as my bridesmaids and then took over everything from my dress to the songs we had, etc. They even went as far as telling me that I was not allowed to change my surname as they were the only ones who had rights to that name.
After the wedding I suffered four miscarriages in a row. I was depressed and had enough of pleasing everyone so I withdrew to take care of myself. They called a meeting with me to tell me how disappointed they were in me that I wasn't making an effort and that I needed to be more considerate if I wanted to fit in.
The thing I am most annoyed about is that two of them 'pretend' to have miscarriages for attention (I know, can you believe it?). I know that they are pretending because one of them had their period (I know as I got sent out to buy her tampons and pain relief) and then a week later when her boyfriend broke up with her, she called everyone to tell them she had suffered a miscarriage. When I asked her if she was sure and if she had been to the doc to confirm she said "yes, I had a test and they told me that my hcg levels were so high and keep going up, so I have lost the baby?!??!"
His other sister announced her own miscarriage shortly after mine - she had apparently known she was two months pregnant, but the weekend before she announced she had lost the baby, she had gone through 2 bottle of wine (she didn't even look at alcohol with her first pregnancy or do anything they say you shouldn't). And the day after, she was in the swimming pool (there was no way I could go swimming when I was miscarrying). She had also told someone else that she was having tests because she had gotten her period twice that month (they asked me how it was possible then that she had been pregnant).
As someone who has lost 4 precious babies, it makes me furious when people say that they have had a miscarriage when they haven't. I would never wish it upon my worst enemy. Am I over reacting or does anyone else find this unbelievably wrong? I can't even stand to be in the same room as them. It's putting so much pressure on my marriage and I don't know what to do