TTC after MC

I had a miscarriage August 17th and then again October 25th. I can't seem to get past 5 weeks. I have three children already but my SO and I are trying for #4 which will be our last. I'm so heartbroken. Two back to back miscarriages. I'm RH- and I'm terrified my body has created antibodies against any pregnant I were to have. We were so excited for this after we lost the pregnancy in August. I feel so hopeless. Any advice from moms/moms-to-be?