Lossing weight without lossing energy

Patient: Iam a teacher and i have tow kids Iam always busy I dont have any time to get rest and suffer a low blood pressure and I must drink a sweet drinks like juse and eat sweet and eat snake from time to time so i can have now low blood pressure or headic and that make me have a big belly and for that Icannot make dite too what can i do or eat to give me energy without get me weight