For what it's worth, I think you're right to go on some 'proper' medication. I was diagnosed at 15 with Still's Disease (a juvenile form of RA) and didn't get anything other than anti-inflammatories and pain relief for some years. This allowed my disease to take hold. I'm far from young now and doing well on a combination of two DMARDS but, if I had my time over, I'd take DMARDS or biologics straight off like a shot.
I think you will have to re-think all the sporting activity though. Exercise is good – vital even – but it should be the kind that doesn't stress the joints. Many of yours sound to be very tough on joints. Swimming and cycling are usually recommended. I realise there's a vast difference between these and team sports but maybe you and your physio can come up with some compromise.
If you re-post about how people find humira on the Living With Arthritis forum you'll get more replies – OK mostly from older people but at least I guess it's better than none
“There is always a well-known solution to every human problem - neat, plausible, and wrong.” H.L. Mencken