My defrosted dough hard to handle once I put stuff on it. I make a horrible mess getting onto the pizza stone. I wind up with at least part of the pizza dough folded over on itself. I never used to have quite so much trouble. I was using a wooden pizza peel; I just tried a metal one for the first time and still have the same problems. what am I doing wrong 
Build your pizza on a square of parchment paper. When you transfer it to the oven, transfer the parchment paper with it. Heat will travel right through the parchment and you'll still get the same browning on the bottom of the pizza. If you are worried about the parchment burning in a very hot oven, you can remove the parchment paper shortly after the pizza is in the oven. After minute or so on a hot pizza stone, the bottom crust of the pizza will set, and it will release from the parchment. Then, you can wiggle the parchment out from between the pizza and stone--the same way you'd wiggle the peel out, except this time with the benefit of a firmer, partially cooked pizza. The parchment paper may scorch at high heat, but there's no danger. 