Why There Is A Headache After Profusely Bleeding Due To Miscarriage?

I have head a headache for five days. Yesterday it was so severe I could not get out of bed. I went to get coffee this morning (a minute's walk) and had to stop several times because the pain was so severe. I hear blood pounding in my ears. Last week lost a great deal of blood during miscarriage, so I am assuming the two are related, but I don't know if I should go to doctor now.