I don't have any advice for you but I can completely relate; I'm finding it hard to find real joy in anything and I'm nearly 10 months sober and am sponsored through AA.
I have a long standing friend who happens to be a psychologist and loves horse riding and she gets a private lesson every week to help build up her confidence and ability (she posts pics on FB all the time of her and 'her' horse) - she has ridden for 20 + years but still takes lessons - maybe this would help you? i.e. start from scratch and do all the basic things all over again? Keep us posted :-)