I have a thick brown discharge, what can this mean?

I've been on birth control for about 8 months, and this last week I was on the last 4 anti-hormonal pills of my pack and i was experiencing a thick brown discharge that I haven't seen before. Now I'm off the anti-hormonal pills and have been back on my regular ones for 2 days, but I'm still getting the brown discharge, only a little less thick than before. What can this mean? Can this mean that I'm pregnant somehow?