I had unprotected sex March 23 and two days later I noticed a little spotting but it went away a few minutes later and reappeared the next day around that same time then had I sex again on that Friday. Leading up to Sunday I began experiecing what seemed to be light cramps but I ignored it and that Sonday at around 6:00pm I realized I started a light flow of bleeding and I'm usually a very heavy bleeder and my menses begins on the 28th without fail and on the third day of bleeding it got a little heavier and now what been day four its now begininning to turn brown and I'm not sure if I'm pregnant.

It sounds like you're just having an off period. It happens sometimes.

If you do believe that you're pregnant try taking a home pregnancy test. Make sure that you use first morning urine and follow the directions exactly.

If it's negative and you miss your next period, or have another off month, try testing again or see your doctor for a blood test.