Certain Times Of The Month I Feel Faint Like I

Certain times of the month I feel faint like I am going to blackout, anxiety and have had my thyriod checked. It is fine. I do get low iron as well and have to take suppliments. If I eat something, the faintness goes away only to return in a few moments or hours later. I feel like it comes on in waves that I feel in my stomach. Valerian helps with the anexity but I am afraid to eat anything.