discharge while spotting

just curious how many of you have had pink and brown discharge with spotting? since my last cycle I had a little brown spotting along with bright red/pink spotting. now I just had it again. my period is scheduled for today I've been spotting since two days ago. since my last period I've been bloated, crampy, pressure like feeling. some nausea here and there and my boobs have felt heavy. I've taken a test but it was negative and I'm not sure if my hcg levels become easier to detect after a pregnancy. with my son I didn't show positive until a little over 2 months and I was still spotting till about maybe two weeks before I got a positive. I'm sure. I'm not pregnant but it is a fear right now. I am on bc so again I doubt I am. anywho about the discharge the pieces that are brown are a little thicker than the pink/red discharge any idea on what it is