Step away from the pizza and take the phone numbers of the places off your speed dial.
I've had the same experience. It could be all of the sodium and preservatives they use . . . also a surprisingly high amount of sugar. And the fats are almost all bad fats.
The downside is it's addictive. As soon as the bad feeling goes away, it's too tempting to order. After a pretty intense take-out pizza habit, I had to swear off of it completely.
I've made my own pizza following an Ornish recipe. I'm not a cook and found this to be very easy (whole wheat flour). Whenever I do this, I make extra dough (for 4 pizzas) and find that to be a great way to save time.
Sandy