I am currently on my period. I am taking birth control quite accurately but miss the odd pill maybe twice a cycle. I have unprotected sex and I typically have a normal average flow period lasting 5 days at most. This time, my period was 5 days late and when it did come it was very very heavy and was just blood clots every time; something I do not experience daily let alone every time time I go to the bathroom. This cycle only lasted 2.5 days. I have been drinking at least 2-3 drinks a night and am just concerned.
Is there a possibility that I'm pregnant? When is best to take an accurate test?m

My cycle started March 11 with very bad cramps which I have never had before and they lasted two full days. The last time I had sex was February 25-27th.