I'm 20 years old and my periods are usually irregular and last 7-10 days. 
Two weeks ago, after my boyfriend and I had sex, I started bleeding a little. I just thought it was the beginning of my period. After a few days it was just spotty and more brown than red. It was weird but I didn't think anything of it since I had two regular periods in a row and it's unlikely for me to have three or more. So it was spotty and it kinda slowed down and almost stopped. Then on this past Tuesday, I started bleeding and it was red and heavier. It hasn't slowed down at all since then. It's heavier in the morning and gradually slows throughout the day. But now there's been more/bigger clots. I was thinking that maybe if I started taking birth control again it would stop. So I took one pill today. My boyfriend always uses a condom. I guess my questions are, should I be worried and should I see a doctor? Thanks.