I am pregnanat or not? Plz reply fast!

I had sex with my husband on 25 june only and my next period date was 15 july but they didnt came and i checked with home pregnancy test 7 times it came negative everytime and i waited till 28 july and went to see gynalogist on 29 july and she done transvaginal ultrasound amd told me everthing look normal there is no pregnancy and told me to wait till 5 august but i had period pain and 2 days of period from 31 july as the blood was less as conpared to my every periods and this was only for 2 days but my peeiods are usaualy for 4 days and today i 21 august i took another test but it also came negative Plz tell my that it was my period or implation bleeding as flow was less and it stayed for two days. I am pregnant or this was my period and i dont have anything to worry about Plz reply fast