What Causes Dizziness During Menses?

i am on me period and have been since saturday for the past few days i have experience dizzy spells and unable to foucus on anything every thing i look at is blurry and i feel sick i have trouble watching T.V and writing this i feel like i have had too much to drink but am completely sober and have not had any alchohol also i am exhausted is this ok as i have nevery experienced it this bad, could it be TSS or i have heard of diabetes during menstrual period?