Ive started my combination pill for the first time on the 7th day in my mestrual cycle amd had unptotected sex on the 13th ,could i be pregnatn?

Maybe. Hard to tell.: If worried about pregnancy, can do a test. A home urine pregnancy test, done correctly, gives a reliable result 3 weeks after sex (3 weeks after when conception might have occurred), or 1 week after missing a period. If done sooner, a positive result is likely real, but a negative result may be due to testing too soon, and thus lead to a repeat test.