What Causes Brown Spotting And Then Heavy Bleeding Before Periods?

Hi, may I answer your health queries right now ? Please type your query here...the past few months when i'm beginning my cycle, I spot very light brownish discharge, at times with small pieces of tissue (not clots). It goes on for about 5 days before I actually need a tampon for heavy bleeding. My husband and I are not preventing pregnancy (for about 6 months now), but i'm just concerned there's something wrong with me...is this normal?