2 periods for last and this month!?

Ik pcos can cause some weird things. But here lately I've been having 2 periods a month. For October it's the 11 thru 22 then next period started Oct.23rd to nov8. Nov.9th to Nov 15. Now it started again Nov 16th and still in this cycle. (Yes I marked my whole cycles from start to finish). But with this period I'm having lower back pain that's making me hunch over and it's an on and off kinda period(lasts for a couple hours then gone). I'm just over it. Like is this even normal with pcos?