I was reminded today of how often lethargy, lack of energy and lack of motivation are common problems with Crohn's and Ulcerative Colitis. I thought this might be useful:
There's a trick I play with myself that works every time - works equally well with my clients..... When there is something they don't want to do, I get them to think about doing it and as their mental video is rolling I get them to say, "It's done!" and all of the resistance seems to evaporate. It becomes easy and they can even do it on autopilot - leaving their mind to enjoy something else.
Hope this helps. If you try it, I'd love to know how you get on.