Stiney,
Make sure that you are eating enough. Your body does need to have enough calories to sustain you, and a diet should not deprive you. Watch your portion sizes, and make sure you get enough protein along with fruits veggies and some carbs.
Once you start some exercise, you will start feeling more energized. Walking is a good way to begin if you don't already have an exercise program.
Don't forget to get a good night's sleep, also. (I know sometimes it is difficult with small children) Sleep deprivation also causes weight gain.
Put that 9 month old in a stroller, and take off on a walk. Having little ones point out things they are seeing outside is a real special time. "Birdie," "Flower," just start walking and pointing out things of interest. You have a 'built-in' walking partner!
Good luck to you!