You have more than likely caused a bout of Telogen Effluvium from the fasting. Your body felt starved for nutrients so it chose to feed your vital organs instead of your hair.
I would stop the fasting for one thing and you really just have to wait it out. I had that happen about 5 years ago just from losing about 15lbs too fast. My hair shed for about 3 or 4 months I think. I learned the hard way not to do that again.