Brown spotting??

As I have PCOS, my period is very irregular. Especially now that we stopped breastfeeding in May, as I didn't have a period until June since giving birth.

Now, all of a sudden, 50 days after my period I have this brown spotting with little twinges here and there, not strong enough to be cramps. Sometimes it seems even more like CM with a little old blood in it. Can this happen when getting your period back? It has been 4 days and I've never had spotting before...

Ps. I'm not on birthcontol.