2 positive tests, then all negative...

So I took two pregnancy tests and they both came back positive... that was 1/19 and 1/21.... now I more recently took two additional ones and they both came back negative.... they were earlier than I would have normally taken them because my obgyn wanted to know when I made my appointment if I was pregnant or not..... my period is going to be starting in the next two days but I am just stressing over what is going on.... anybody have the same issue or anyone have any advice??? I can only read online articles so many times before I go completely crazy!!