Update:
11 days ago I started getting really sharp back pain in my lower left back, like knives between my ribs. It has since gotten better, but now I have a constant dull pain in my lower back, and I generally feel like crap. I have barely slept for two weeks and I haven't been able to get myself to the gym. Last week it was so bad I just had to get a sick leave from work.
So it seems like I can't keep it at bay with exercise alone
On a lighter note, my previous blood test from march was a liiiittle bit better, AND I got approved for another anti-TNF (Cimzia), which I can start on as soon as my next blood test checks out. I took the blood test today, so I guess I will get a phone call soon, so I can get back to work and the gym again

crossing my fingers!
My goal for this year is to put on another 10kg (22 lbs).