help help someone please what do u think

Haley
Ok so it’s Thursday. My period was due Tuesday but I didn’t get it yet.  I know this is awful but me and boyfriend have unprotected sex. He always pulls out. Always. Sometimes we use condoms. Sometimes we don’t. Anyways I thought it would a good idea for obvious reasons to go on birth control. 
I finally received my prescription and I took the first pill on the Sunday after my period. 
I started reading bad reviews on that pill so I decided not to continue this certain pill. So I only took one 
Is it possible my period is late because I took that one pill??