You will probably be best off by just adding the ADY to the warm water with just a pinch of sucrose (regular table sugar) to help get it started. There is no need to add any flour or anything else.
If you have too much yeast for the length of time you are fermenting the dough the dough can become over fermented, thus weakening the dough to the extent that it can't support the weight of the toppings, so it now collapses, and readily allows heat to pass through the dough/crust into the toppings where the heat is dissipated in the form of steam, hence the dough never becomes baked to the point of being very crispy or firm. If you see both of these in your pizza, the dough might be over fermented. If you just see the gum line you might also be stretching the dough too thin, or if you are making your own sauce, you might be adding too much water to it, or an excessive amount of toppings. To test for this, try brushing on a VERY THIN layer of oil on the skin, then add thin slices of blotted, fresh tomato (one average tomato is about right for a 12-inch pizza), now apply your cheese and see if the problem has been addressed. If it has, this is an indication that you just need to work on dressing the skin. In some cases the gum line can also result if the pizza isn't baked long enough. To test for this, reduce the baking temperature by 50F and bake to color. If this addresses the problem you may need to make an adjustment to your baking time and temperature.
Tom Lehmann/The Dough Doctor