100 lbs. in 2 1/2 months? No way dude. Not safely, and I don't even know anyway that's possible. You'll have KRAZY skin after that extreme weight loss.
Shoot for something reasonable like 40lbs. and maybe try Atkins or Keto diet with NO sugar. Take out sugar totally and lower your carbs, you'll lose weight. And energy. But if you want it, you'll push through.
What kind of activity do you do now?