It will go back to normal...we drop the baby weight really fast because of breast feeding and burning all those calories during labor :) im looking forward to it...I look like the mythical great white whale...
Things won't likely go back exactly they way they were. Pregnancy takes a toll on our body's. You may find that you have a bit of extra stomach pooch or maybe your boobs aren't as perky as they were pre pregnancy, but it all comes with the territory. You can definatly return to pre pregnancy weight and shape though. Some of us have to work really hard while others find the weight just falls off. Whatever the outcome, you'll learn to adjust.
Also stretchmarks r genetic so cant really prevent them.
Use palmers coco butter to prevent stretch marks. Or at least make them less noticable if you do get them. Keep a handle on your weight gain. And ask your dr about continuing working out or starting to work out while you're pregnant. :). I do yoga and walk and do light weight lifting. .you'll get your body back. Just takes a little work!