Hi Candy, I'm so very sorry for your loss.
Firstly, as others have said - this is not your fault. Nothing you did or didn't do would have made any difference. I lost my first pregnancy, my little tiny tiny baby at 5 +2 weeks in November. I too blamed myself and thought about every little thing I'd done and tried to link it - stress at work, a medium rare steak before I knew I was pregnant, there's a long list. But I'm now accepting that none of that made any difference at all.
Secondly, you are completely normal to feel jealous about your sisters' pregnancies, this should have been you too, it's natural to feel angry, sad and a whole range of emotions about it, while still being happy for them too. Time will heal, I can promise that. I have quite a few friends with tiny babies, and although they were really sensitive to my loss and asked if I'd rather not see them for a while, I actually found baby snuggles and talking to friends who have carried a tiny human in their belly and understand some of the feelings I was going through (about how attached you become, even at an early stage) really really comforting.
Miscarriage is still one of those taboo subjects. People don't like to talk about it often, perhaps because pregnancy is seen as such a happy time and the loss is so devastating. But I've found that talking about it really helps. So many of my family and friends have told me their own stories of loss, and then hope again. It will be very personal to you how much you want to talk about it and who you want to tell, just don't feel that you HAVE to keep quiet if you don't want to.
Finally, I wanted to offer you a tiny bit of hope. I miscarried at the end of November. On Christmas Day I found out I'm pregnant again. I'm really nervous, but feeling positive. As other ladies have said, the EPU or your GP will most likely tell you that waiting until after your next period to try again makes things easier for dating. But medically, once you've recovered physically from this loss, and to a certain extent emotionally too, enough to want to try again, there's no reason not to. So when the bleeding stops, and when you're ready, be that a few days later or a few months later, try again. Sending so much love and a big hug too. 