Lighter than usual period while on Levlen ED - unusual for me

I'm on Levlen ED and have been taking it for almost 2 years now. I always get my withdrawal bleeding on the 3rd day. It usually comes with cramping that is painful but nowhere near as severe as before I started the pill. This time around it still started on the third day, but it is much lighter than usual, with no bleeding at night which is very strange. What could this mean? I have been fooling around with a guy recently but we haven't had intercourse. Our only form of protection has been the pill. Could my hormones be reacting to sexual activity after a year of none, or could this be a sign of early pregnancy despite no penetration? Thoughts?