Talk to Gynecologist on 7th Week Of Missed Period. Not Pregnant.

I always have had regular periods. I got my last periods from 15th March to 21st March. My next periods were due a week before eid, around 17th April. This is the 7th week and I have not got my periods yet. I did upto 4 urine tests using strips last week and the week before that. All were negative.

I'm worried and not sure how to go about it. The only thing that comes to my mind is, I do running or workout upto 3 times a week. but that is not abnormal. I have been doing it earlier too and getting my periods on time.

Please advise.