I was on Humira for 2-3 years and it worked pretty well, sometimes a little TOO well as I would often feel constipated. Although, constipation in my world is not going 5 times a day! I was able to follow a fairly normal diet while on it, I could even occasionally eat things that are normally off limits for me such as red meat or fried foods. I don't know if it has this effect on everyone, but it did make me gain a good bit of weight. Which wasn't entirely bad because I was pretty skinny before.
I'm not sure how proactive you or your doctor are about monitoring your vitamin/mineral levels but I would be sure to stay on top of these, as well as your kidney and liver function. One of my friends is still on Humira and said it never helped her until she started taking it along with Azathioprine and B-12 injections.. Besides, making sure you have proper nutrition is NEVER a bad thing, and you would be amazed at the difference it can make.
Wish you the best of luck and hope it works well for you!