Lost my virginity and still haven't gotten my period?

I know these questions are redundant but I lost my virginity around march 12th and I still haven't gotten my period full fledged. The last time I truly got my period was the last week in feb. I took 2 HPT and they both came out negative. I went to the doctors and they also ran a urine PT and it came out negative. I sort of got my period like last week, I mean it was brown blood and pretty light so yeah. Protection was used but I'm not exactly on the birth control pill so what are the chances of me getting pregnant? ARGH!!