Help with oa

Hi , I have recently been diagnosed by an xray with OA in both knees I have been in chronic pain but this has been eases by stetrod injections and naproxen and cocodemol. My gp has not been very supportive and just blames my weight and has now said he won't give me anymore steroid injections and has basically said if I can't lose weight in the next few months then he can refer me for weight medication or weight surgury. I have been slowly loosing weight since my symptoms started but this is increasingly difficult because of mobility issues. I just wanted to know if this was the normal next step treatment as he has said that he is 100% sure my pain will go once I loose weight. I am 55 and 5 foot and weight 14stone 7lb