I'm having some issues myself, my GI let me up my Humira to 2 shots every other week. Maybe you could try that. Your question about the Humira failing, is kinda making me wonder the same thing. But.... I kinda doubt it... I sure hope not. ;)
27 year old, Married, Female.
Diagnosed with UC since March 2007
Taking Humira since of May 2007 (Currently in remission since May 2007)
Put on Imuran from May 2007 to Jan, 15 2009
Put on Canasa June 25, 2009, off Canasa on June 30th 2009.
*Can't take Asacol, Allergic to Remicade, odd reactions to Canasa went backwards a bit.
*Started minor flare in mid June 2009 but VERY minor. :(