Is it fainting during periods normal?

[beautynbrainz]

Is it normal for one to experience lightheadedness and fainting during menstruation?  It's happened to me so many times before, typically as soon as my period/cramping starts I'll feel lightheaded, sweaty, and I'll fall to the floor and sit with my head on my knees.  Occasionally this happens in the shower, or upon standing up if i wake up with my period, or even if it starts while I'm seated during a class. I don't really think heavy bleeding is the cause, I think its normal, but I mostly have sever cramps for the first two days that make me double over in pain and then it goes away. Although these cramps are terrible, I live with them and after the first day it doesn't keep me from daily activities.  
I am 18 but I admit that I don't exactly feel up to telling my parents about this problem, unless its serious...is it?  Also, I have been dealing with thyroid cancer for the past 2 years, so of course I have had my thyroid removed and I am taking synthroid.  As far as birth control pills, I know if I start I'll need my dose of thyroid medicine adjusted, but I'm scared to even bring this up at my next endocrinology appointment with both parents present.  I dread having to deal with starting another medication because I have experienced hyperthyroidism when my dose of thyroid meds were too high for me and hypothyroid when I had to stop taking meds for treatment :(

[beautynbrainz]

thank you so much for your reply! I do have a physical on Thursday to renew my  ADHD Rx so maybe I'll mention it at the end of my appointment, I can't believe how scared I am to mention it!  I think you are right, I don't really eat very much but I try to now since I'm taking adhd medicine. I forgot to mention that i do take multivitamins that have iron and calcium if that changes anything...
but thanks again!!

[trekrgirl]

Although this is not normal per say, it can be caused by your period, a heavy flow can do that.  You may be experiencing some low blood sugar levels try keeping some snacks handy like a granola bar or even some chocolate.  When you go to the doctors, see if you can mention to the nurse you would like a private minute with the doctor and then you may be able to bring up these concerns, or you might bring that up to your Mom prior to your next appointment.  I am sure your Mom would understand, just explain you feel uncomfortable brining it up with both on them in the room, maybe she would let you have time with the doctor and then all of you you could have a couple minutes after the main appointment.  If you are 18 you can make your own appointment with a gynecologist or General Doctor.