Bleeding in second trimester

This is my first pregnancy and I'm about 15 weeks and 3 days along. I have have bleeding about 3 different times now within the past 3 weeks. It's very light and light in color and my obgyn said I don't need to seek medical attention unless it's heavy and dark. My question is has anyone else ever had light bleeding? In any trimester? I see my doctor Monday so I will discuss it with her then.