sudden hair loss at 22

I'm twenty-two years old and after a couple of months dealing with an ulcer, i lost a considerable amount of weight in only a couple of months. I was taking two Zantac everyday in the beginning for a month or so, then I was prescribed Nexium which I took for two months. I've been losing been rapidly losing my hair ever since, I've since started being able to eat normally again and haven't been on any medication for two months now but my hair still is coming out.

My scalp is considerably dry, itchy and has these moments where it feels like something is crawling all over it. There is a mild burn at my scalp and when I rub my hair with my hands, a considerable hair falls out. The hair looks like it's broken and some are very short and wirey, most have the little white thing at the bottom still on it.

I don't know if this is permanment but I've never had anything wrong like this before - I've always had thick hair but it's a lot thinner all around. I was wondering if this is permanent or if the hair will grow back because I think I'm a little to young to be losing my hair at this rapid rate. I realize that hair does fall out and I have a history of male pattern baldness in my family but I know it's over a long period of time - this hair loss is happening all in a couple of months - and I've lost so much already.

What's happening?