Confused, tmi but anyone know?

So I was five days late for af and had some unusual cramps and I was getting hopeful but four days ago I got some stretchy brown cm and I was still like weird but the next day (after it was on and off) it went to pinkish brownish and got slightly heavier than a spot but not enough to fill anything forreal and it was on and off for that day and the next. Yesterday it stopped completely. Now today I have almost black discharge. What could this be? Do periods come and go like this? It's brown and stringy like cm ...