Question (tmi, no pic)

I always get some brown discharge before my period but usually it's light and just a couple days. This month I had the brown discharge but for a week and it was heavier. The last day before my period started it was super heavy brown clumpy (mucous like) and I've never had it like that before.  Any ideas what happened?  Then last night AF arrived full blown... Very heavy. I'm just wondering if anyone has experienced anything similar.