S.B.
It takes time. My first pregnancy resulted in a miscarriage and it was devastating. We had to take time to grieve the loss and had to take time to accept that we may or may not get pregnant again. Miscarriage is not a result of anything you did or could have prevented. Something was wrong with the poor baby and your body knew it would not survive. Miscarriage is not an indicator that it will happen again. Basically...you just have to take time to heal and hope that you are able to get pregnant again soon.
It took me over a year after my miscarriage but I also have friends that got pregnant right away after their miscarriage...so you just never know. I will say you will probably worry more when you do get pregnant. I was spastic the whole time in fear of another miscarriage...but I have 2 beautiful healthy girls now.
I don't know the circumstances with your SIL but I do have to say it is pretty normal for you to feel bitter and angry towards her. You just lost a baby and here she is pregnant without even trying. Those feelings will pass soon. But I do think it was rather insensitive of her to call so soon after you miscarried and told you. :(