Cannabis?

I've had diabetes and abnormal weight loss since I was 6 years old. When I reached my teens I started to use cannabis to help my health conditions and depression ect. It helped me out a lot! But then I stopped because I didn't need it or want it anymore. I'm now 19 years old and have a son with my boyfriend and my health and weight is horrible. He doesn't care about my diabetes or care enough to help me out with anything. And every time I bring up using cannabis to see it will help me in anyway he gets mad and tells it wouldn't help any and make me a bad mom. Well I can't be a good mom if I'm always sick like I am. I don't know if I should just go behind his back and try it and see if it helps or just accept my fate.