Hi I'm 17 and I have sex with my boyfriend and we did use a condom. It was 2 weeks after I had my period in February 23. Then in march I took 3 pregnancy test at home 2 were positive 1 negative so I decided to make a doctors appointment march 18 I got my period march 17th and it wasn't normal it was light so I went to my appointment and then I started bleeding more then the first day on the 18th the doctor said I wasn't pregnant so then on the 19th it stopped and it started again the 20th I really didn't care because my mom said my period could be getting normal finally. Then on the 28th of march I went in for a blood test it came out negative (my period is usually dark heavy and a week long) well now its April 14th and my period isn't normal like nothing comes out when I whip or on my underwear but when I have a tampon in a little bit of blood comes out it started 2 days ago and today it stopped

If a blood test said you are not pregnant and you did not have sexual contact following the blood test the probability is that you are not pregnant.

For whatever reason you are having problems with your cycle - what does your Doctor say?

She didn't say anything she just kind of said it was because I was sexually active and she wants me on the pill but I said I didn't want to be on it and she put the pills at the pharmacy just in case if I change my mind and then she put that I was taking them but I'm not so my doctor thinks I'm on the pill so they think its because of the pill

The only way to know for sure is to go to your doctor. From the sounds of it, I don't THINK you are pregnant, but then again I am not a doctor.