Thought I'd put some perspective:
The body regenerates hemoglobin. "50 blood donors did 175 transfusions, and rapidly returned to normal" and "Certain donors exhibited such regenerative ability that the withdrawal of 1,200 to 2,000 cc. of blood within a period of one to twenty-three days was followed by a return of the hemoglobin level to normal within ten days"
Now, this is still a very dangerous and stupid thing to do, no offense. There's a test you may be able to do if you're worried, because methemoglobinemia discolors your blood arterial blood to a "chocolate, dark-red, brownish to blue " You'd need to take a syringe, and take a sample of your artery. However, as long as you take very low microdoses, you're probably fine. Just make sure you separate doses by at least a couple days, so that your hemoglobin is definitely restored.
I do not recommend this practice, as it could have dangerous side effects. Do at your own risk.