1. Don't use Prego and WHOA DON'T USE PASTE. Buy a can of whole peeled plum (sometimes called Italian) tomatoes. Wal-mart sells them - $0.88 for a 20oz can. Of course better (usually more expensive) brands are higher quality and have less water content. When you open, drain some water out and then crush them with a potato masher or, if you have it, an immersible hand mixer (
like so). The more water you get out, the less watery your "sauce" is. Feel free to season with whatever you like, I just use kosher salt.
2. Adding more sauce to less dough is actually even worse. It's different with pan pizza but sauce is wet. The more you put on, the heavier and wetter you make the pie. Dough absorbs moisture, especially while cooking. Lift up the cheese on your pizza. See that gummy dough? Look at it from the side, there is a little band of it, like a ring in a tree's trunk. That is known as the gum line and it should be less than 4mm think. Any thicker and you're using too much sauce. If you don't have enough dough then you don't have enough dough. Adding more sauce or cheese or toppings just makes it worse, and harder to hold. Try not stretching it as far, or letting it rise a little in the pan, which can make it a little thicker.
Now I want pizza.