My fourth miscarriage!!!

I had 3 chemical pregnancies and one blighted ovum . I have no kids . I went to a fertility specialist he did all the blood work I needed and everything came back normal . He suggested I take 50mg of clomid the lowest dose so I did , after taking clomid for 3cycles I got pregnant but I started bleeding.It was a chemical pregnancy,after that He wanted me to take progesterone this time after I ovulate, but I'm scared that I'll keep having chemical pregnancies... did anyone have the same or similar experience ?? I need help , I don't have trouble getting pregnant its holding a baby I can't do ..