13 Chemical Pregnancies

Has anyone else had a lot of chemical pregnancies? Me and my husband have been trying to get pregnant for about two years now. In that time I’ve had 13 (I know it’s a lot) chemical pregnancies. I get pregnant just fine, but I don’t stay pregnant. And the weird thing is that they all end right before or on the day of my expected period. I’ve only ever made it to four weeks. I know that I am getting pregnant though: those pregnancies were confirmed via blood test. Has anyone else had this issue? I have been diagnosed with PCOS if that helps and I have some other signs of autoimmune issues.