Weightloss and pregnancy??

So my best weight is 126 and normal about 140, i gained alot of weight die to stress this is my 3rd baby i dropped all the weight after my 2nd in 6 months but felt horrible this time around getting pregnant at 168. I jave never had such a high prepregnancy weight im only 5'2. Does anyone have any weight control or something to maintain while pregnant? Im 12 weeks 4 days and already 172. I know the heavier i get the harder the rest of my pregnancy will be please help!!