i had unprotected sex on 1st of febrauary.missed my periods which was due on 22nd feb. now its 20days since i had my missed period. i did urine preg test abt 3 times all negative with morning first urine sample.then on 10th i did beta hcg and the result was 0.8m/U/ml.i went thru various sites in internet and they say its normal in adult below 5m/U/ml. again after 3 days i did a rine preg test and was negative.i am really very worried about what is going on. is the missed period because of stress or pregnancy.please help me out.