Hi Doctor, I had my last periods on 23rd April 2013, and i had intercourse (first time) on 4th May, without protection. The guy didnt ejaculate but some pre-cum was there. now since this month I should get my periods on 20-21 May, I am still not having my periods. is this a cause of worry? should i get my pregnancy test done? i am extremely worries. Looking forward for your immediate response