Blood work?

I had my TVH on 5-25. Kept my ovaries. however I have a feeling they are not working or they are about to crap out. I feel tired ALOT more then I used to. I have Killer headaches all the time and I have some vaginal dryness.
I wanted to call my doctor about having some blood work done. Is there a better time of the month that I should have my blood work done? I know this sounds dumb, but I don't know. I honestly have no idea when my cycle would of started and ended now that I had my TVH. I was not regular to begin with. So I guess I wondered if it mattered when I had the blood work done or not. Is there a better part of the month to have it done?
Thank you Ladies.

i don't know if it matters, but you're doctor would know... i'd suggest giving them a call and telling them the symptoms you're feeling/having...