What Causes Extreme Fatigue With Nausea And Headaches?

Hello, I have Polycystic ovarian and Hyperinsulinanemia with irregular periods, although if I keep a calendar I ovulate when I am supposed to, even if I missed the last couple month cycles I will have my period on the 86th day.... I am 32 years old and have 2 sons ages 6 & 8. My husband and I are TTC for 3 years... but I weight 330+ Lbs ... so this has not been easy ... we have not been as... diligent lately and approx. 3 weeks ago I began spotting brown for 1 week... then light pink for 3 days ... then a very very light "flow" for 1 day ... now back to spotting again... from beginning to end 3 weeks. I have had extreme fatigue, consistent nausea in the evenings and headaches almost everyday, I have also noticed that am a lot more irritable and hungry... what could be going on?