Advice

[Nelson Vergel]

My endo so busy he cant see me for a few weeks so I paid privately to have another 1 unit drawn, and headaches etc stopped.

What is your blood pressure? High BP can cause headaches.
In my opinion, the best indicator of the need for blood donation is high blood pressure+ hematocrit above 52. Having normal blood pressure is an indicator that your blood vessels are still handling higher hematocrit OK.