Psoriatic Arthritis

Hi. I have been suffering with Psoriasis for twenty one years but in the last year or so, I have been diagnosed with Psoriatic Arthritis in my knees, one ankle and the bottom of my spine. I'm taking Humira Injections for my Psoriasis but nothing is helping my joints. All I have been told to do by my doctor is to lose weight. I have lost over two stone and I'm still in a lot of pain. I was wondering if anybody had any ways of helping me without medication? My doctor won't give me medication until I lose four stone.