I had this at exactly 11+4 last week. It was all pink though, and days before that I had a little bit of dark brown in my cm. I had an ultrasound on 11+4, and the baby was bouncing around with a heartbeat of 162 and I was put ahead two days.
The only thing I've read about this is that our uteruses are really growing as the baby doubles in size in the next couple of weeks, and your uterus lifts up and out of your pelvis. I think with all that movement, we're bound to have some cramps and even some drops of blood. Always speak to your healthcare provider, but in my case, this is what has most likely happened.
The brown stuff lasted on and off for almost two weeks, and the pink only lasted one wipe in the morning. I haven't seen the pink stuff again, and the brown stuff has been gone for days.
Also, my symptoms have really faded over the last few weeks. Don't worry about that either - it's bound to happen at some point. My doctor told me that just like when you're not pregnant, you have good days and bad days. My symptoms will disappear for a few days, then all of a sudden, they come right back!