Can sex affect the flow of your period?

So here is the deal..

My boyfriend and I have had sex three times. We used a condom and correctly, I might add. The first two times he didn't climax and the third time, he did but he took it out before it happened. Remember, we used a condom all three times correctly.

My 'Period' just came last night but usually on my first day, its super heavy. Today, its rather light. Can sex effect the flow or is something up? I've never been this light before.

Sex might affect your periods.
Since you used a comdom which is good, I would go to your doctor if your periods continue to be light. I'm not saying that there is something wrong though, I'm only saying that if your periods continue to get light again, to see your doctor. I wouldn't do that again.
But, its your choice to continue to have sex.

yes,sex changes tthe flow,color,consistency, and time at which your period comes. some girls have a light flow throughout there period,some heavy. but sex will most likely change how you have your period.