2 times abortion. Is happening to me.

I went through all tests and examination all good.. 10 years back my1st pregnancy was very smooth...2 years back i got pregnant through ovulation indection bcs i thought do want to wait for 3 or 4 months to get pregnant so went for ovulation induction but I traveled bit and at 7th week i got missed abortion...After 6 months i got conceived naturally and everything was fine but in double marker test it says screening Positive but triple marker test there is nothing to worry but i didn't want to take chance as i was afraid of down syndrome baby so i went for medical termination...and after 5 months again I conceived by ovulation indection and upto 11 weeks 4 days everything was fine but all of sudden i got heavy bleeding and got abortion due to low laying placenta...why this is happening to me..? Should I forget to have one more baby..? I can't have..? Please let me know