What happened to me?

While i was in the shower, all of a sudden my vision became very blurry (and had a blue-ish tent) and i became dizzy and disoriented. I also felf very weak and i could barely stay standing. I had to turn the water off and lay on the floor with my knees bent until the feeling passed. I was very scared during this and this evening i noticed that my hair is slowly falling out. I also have a slight headache and recently if i stand up too quickly, i become dizzy and the blue-ish and blurry vision returns. This goes away after a few seconds though. I do not eat much meat (absolutley no beef) and i was wondering if i have a mineral defeciency. I really need some help because i do not want this to happen again. I am a 16 year old male.