What Causes Fatigue, Influenza And Weight Gain After Partial Hysterectomy?

I am a 48 yr old female who had a partial hysterectomy when I was 28 w/or issues. At 40 I had my Right ovary removed d/t a large cyst (from scan was 3cm but when they went in to remove was actually the size of a baseball. I have never been the same. The doc said I would be up & back to myself within 4 weeks and I was back to normal life but my energy level was so low and I would have a spell approx once a month where I would have crushing fatigue, felt like I couldn t hardly move, felt sort like I had the flu and would be freezing one minute and then get so hot the next. These lasted about 12-24 hrs and would occur sporadically for about two years then just went away but the low energy never went away. I am scheduled to have my last ovary removed Monday 5/11/15 and just wonder how it is going to affect me? I m really scared! This ovary is being removed d/t another cyst that has been growing for a year but most of the growth was in the last 3 months. Should I have it removed? Why have I not been offered to just remove the cyst? What side effects can I expect? Just FYI: I was considered hyperactive before I had my 1st ovary removed at 40. I also have been thin all my life but in 8 years I have gained 10 pounds - will I gain more? Any information you can provided would be so helpful and very much appreciated! Thank you in advance for your time!