I've been (am) in your situation, also ex-dancer. I recognise that pain all too well. Not sure how old you are, but in my 30s and after two pregnancies I thought that my lower back would cause me to stop working, as I couldn't sit down all day.
I have tried chiropractors, physio, osteopaths etc and although I still see a chiropractor every week (and probably will have to for the rest of my life) the one thing that 'saved' me was facet joint injections.
I would recommend that you go to your doctor and start the process from there. I had x-rays and MR scans to determine the problem and from there I 've had three sets of facet joint injections (and an epidural, which didn't help).
Although I am not 100% pain free, my life has dramatically improved and most importantly I can keep working and provide for my family.
PM for more details if you wish