Hello I am 22year old. I had my last periods on 30th June. They usually last for 4days. I had unprotected sex on 11th July. My periods haven't come yet. They were due for 30/31st July. I again had unprotected sex on 13th August. I took Preganews test in the afternoon before the intercourse. It came negative. I had sex after the test. Again, on 14th morning, I did the Preganews test again with first urine, it again came negative. To be sure, I took serum beta HCG test for pregnancy on 14th August afternoon. It came negative on 15th morning. My periods still haven't come. I am very much worried. Can there still be any chance of me being pregnant due to the unprotected sex on 13th August? What to do? Please suggest.