Hi everyone! 
I am ttc and I experienced the strangest thing last week. Usually my cycles are ~32 days, moderate to heavy, 5 days on the dot, and I always have PMS like clockwork that starts 5-7 days before (very sore breasts, a bit of nausea, etc).
This month, 28 days in, what I thought was AF came without warning. No PMS, and only mild cramps (barely noticeable) lasting ~5 mins. This AF was lighter than any AF I have had by a decent margin. And the kicker? It was brown (sorry TMI) from start to finish and lasted closer to 4 days than 5.
This is different from anything I've experienced and unusual for me, but from what I've heard about IB, I'm not sure. It was much lighter than usual (and brown the whole way through? Weird) but definitely heavier than what I'd expect spotting to be.
I still have no PMS symptoms. Nothing.
Any thoughts? Have you experienced anything like this before while ttc or before?