Deprovera

I am 40 years old and took the Deprovera shot for 12 years due to weight gain just in this last year my primary care doctor advised me to stop taking the shot because he could not find any other reason for my weight gain. Now I am terrified because Deprovera was the only birth control method that has worked for me ever. I conceived a baby on birth control pills. Also when I did plan to have a baby I had taken birth control pills for 7 years and it only took me 2 months to get pregnant after I stopped taking the pill. Now I am wondering what will I do for birth control. Any suggestions? And is it possible that maybe I will not be as fertile since I have taken the Derpovera Shot for 12 years and not really had a period for about 9 of those years. I also loved the way I felt when I take the Deprovera shot I have energy and I don`t have mood swings or headaches. When I took pills and had periods I would only feel good for one week but with Deprovera shot I only start feeling bad when it is close to the time to get my shot. After about the first week after taking the shot I feel energized. Is there a hormone that I could take that would help me feel that way but would not make me gain weight. Please give me feedback.