Could Weight Gain Be Due To Morphine Sulphate?

Hi I am on morphine sulfate 5md 1 tablet 3 times a day as well as morphine sulfate 60 mg 1 tablet twice a day. I was prescribed that after being on oxycotin and Percocet and it not working as well as it used to. I have gained weight and have had weight issues growing up and am severely getting depressed. I have degenerative disk disorder with a defraging disk, if that makes sense. I wanted to know if there is a pain medication that will not make me gain weight or even one that I can take that will help me lose weight.