Irregular periods, progesterone levels & PCOS

hi everyone, 

im new to this group. I am 27 years old and have been on the pill for 10 years. I came off it 13 months ago and my periods have been very irregular. 

Last pill taken 26th May 

1st June first period 

6th September second period 

12th december third period 

24th jan fourth period 

4th march fifth period

15th May sixth period 

16th June seventh period

I have been to the doctors and had 2 blood test both with low progesterone levels of 2.2 and 3.0. I am now booked in for a ultrasound scan to see if i have any problems. My recent period i had red blood for an hour then the rest has been brown blood. 

has anyone else been through this?