Hello Doc I Got Married In Nov 19 2013. I

Hello doc
I got married in nov 19 2013. I missed my period in dec on 25th.n checked for pregnancy. It ws positive. But on jan 1st it got self aborted. Doc said it ws early pregnancy n I didnt need any surgical treatment for complete clean up.
in may I again got pregnant n again same case happened.i lost my pregnancy.
this time doc had done 5 pregnancy related test to know the reason of these two miscarriage n all were normal. I ws found wid no negative test.
I wanted to know what may be the reason for this?
Let me add that i hv regular 28 days cycle and hv no other health problem and also me and my husband never used any protection bcz we want a child.
My doc hs prescribed me folic acid for 4 weeks and nacfil 600 mg for 15 days and I m taking these pills now from last 5 days.am I on ri8 medication? Can I get pregnant now? My last period date is 22oct. And i am 25 years old 5 feet 5 inch 56kgs.
please help.
thanks