I'm pregnant and want to know what kind of exercising i can do. or if i can lose weight while pregnant.

Exercise is good: You can continue a program of cardio/aerobic exercise (brisk walking is great in pregnancy) and running is ok especially if you regularly ran before pregnancy. Strength and flexibility training are also fine. Gaining 15-25 pounds during pregnancy is recommended, but if you are quite obese, not gaining while eating healthfully and exercising, with your doctor's blessing, may be fine. All the best:)