Black outs/Ceizures

Hi, I'm a 17 year old female and I'm slightly anemic. I was presribed medication to boost my iron count, but have neglected the treatment. (I dont like taking medicines)
Well, I have had some problems with blacking out. Two years ago, at a music festival in VERY hot weather, I blacked out and had a ceizure that lasted just a couple minutes. (I was also using "shrooms", but didnt know if that had anything to do with the heatstroke) It started by me standing up, when my vision went black for a second but that is normal when i stand up because of my anemia. But then when i started walking, my vision became more and more black and my hearing went out, too. After about 20 seconds of trying to walk, i fell over and went unconcious into a ceizure for about two minutes.  
A year later, at a concert in a small, packed, and once again, VERY hot venue, I blacked out once more but I never went unconcious. Luckily i had someone there to drag me to a cooler area and get me some water. I was completely sober at this time.
And now, it has happened a third time which is why im concerned.
When i drink alcohol, it is only on special occasions so i guess you could consider me a light-weight. But last night, I had 4 shots of rum, which doesn't seem like enough to have this outcome: I was sitting in a chair in an upright position when my vision started darkening and becoming blurry. It seemed like the black was pulsing from the outside of my vision point and moving inward. I was very nervous because i was afraid of another ceizure. When i turned my head around to look behind me, my vision suddenly COMPLETELY blacked out and when i turned my head back around it took a minute to lighten up some, but i could still barely see. My hearing also started going out, and along with that, i heard an odd crackling/suction sound in both ears. It took me a few minutes of sitting to be able to get up and move at all. So when i had the strength, i went to the bathroom and threw up a tiny bit. I then moved to my bedroom where i layed, trying to just wait it out so it would go away. Finally, my hearing started coming back and my vision was no longer black. I had a good dinner last night a few hours before drinking so its not like it was caused by drinking on an empty stomach. Also, a friend who stopped by brought me a jamoca shake and some curly fries from arbys. I drank/ate that after three shots, and then had my 4th after that. Then 15 minutes later is when all of the blacking out started. How could that have affected it?

I'm sorry for such a long entry, I just dont want to leave any important details out.
I have no idea what this blacking out is caused by and would like some insight from someone more educated than me on this subject.