Why would my period be so irregular

Angie
I know my chances of anyone here being a doctor is low, however I'm just concerned and I can't get into the dr until July (insurance issues)
I'm on the NuvaRing birth control and have currently been since January 2016. My period had always been very regular even before NuvaRing. 
Then in Sept 2015 it was 21 days late and very light.  Oct it was normal, Nov I missed it, Dec it was 3 days of spotting. Jan it pretty normal-4 days, Feb 4 days late but again 4 days March I missed April 6 days late 5 days long. And I just had my period for May- 4 days late and bled 1 day. 
I'm kinda psyching myself out thinking it could be PCOS- as I have a few other symptoms, wondering if maybe someone else has experienced anything like this.