Could i be poisoned by iron im really scared

I feel really light headed and dizzy. I also feel nauseous to the point where i may throw up. Is this normal.

I took it so my period blood would stop flowing so much. It stopped but now I feel sick

I was prescribed the iron to take three times a day because I'm anemic so that's why I have it. I only took 250mg over my recommended dosage

My doctor told me the iron may help my period go back to normal because I've been getting 100 blood clots per day and my flow is heavy which isn't normal for me. I used to use one tampon per day or maybe two now I use at least 5.

I'm 14 BTW