Is my hermit crab dying?

I got my hermit crab 2 months ago. He is relatively small. He fits in a shell that is just a bit bigger than a quarter (the currency). On Friday, he was dropped about 3 feet, hit the tile floor (not my fault, I was not holding him someone else was) since Friday, it appears he has lost a leg, and today (Monday) he lost his big "pincher" while I was holding him. I was not touching him, just the shell. I am really scared, I don't want them to die, for they mean so much to me. (I have two, and it is the smallest that this is happening to) I don't know if this is how they shed or what, but please help me. I don't want them to go...