The Real Answers team answered a question that I think addresses yours really well: http://ubykotex.com/real_answers/qa/answers?id=52391. Basically, our health experts said that any type of cramps can cause lightheadedness. So can anemia, which is a common issue for women on their periods. But of course, if you find your symptoms are getting worse, you might want to schedule an appointment with your healthcare professional. Also, see what our health expert, Michelle, has to say.
If there's anything I've learned it's that there's no such thing as “normal” when it comes to periods. There are a variety of symptoms that girls face and menstrual cycles affect each of us differently. Dizziness is symptom that some girls face. I've heard that drinking plenty of water and taking ibuprofen according to package directions can help. (If you're under 18, make sure you talk to a parent or guardian before taking ibuprofen, though.) It's also important to eat healthfully during your period — include plenty of fruits and vegetables, lean protein and whole grains.
Prostaglandins produced in the uterus are hormones most commonly known for causing menstrual cramps. These prostaglandins can affect other organs as well, causing various other menstrual symptoms. Headaches, nausea, diarrhea, back pain and yes, dizziness. Symptoms resulting from this surge in prostaglandins start a few days before flow begins and taper off a few days into your cycle. Ibuprofen inhibits prostaglandins and can be used to decrease symptoms. Also anemia, which is common in any women with a period, can contribute to dizziness. Make sure you take care of yourself, especially when you have your period. Eat a well balanced diet, don’t over-do the salty carbohydrates and sweets because this can actually make you feel worse. Drink plenty of water, take a multivitamin and get about eight hours of sleep each night. Dizziness during this time of the month is unlikely to be of concern. However, if symptoms persist, contact your healthcare provider for an office visit.
@sara I have felt the same, I am on my period now feeling dizzy, and light headed. I have almost passed out outside while taking my sisters to the bus stop. All i seen was blackness and I couldnt feel anything I felt like giving up but I didnt I went back to the house and knocked on the door till my mom came to get me from the front door. And if yall feel dizzy early in the morning while on your period please take your time getting up, and drink plenty of water." - MsDohnut