I decided that I want to try doing a mini triathlon. I think that setting goals for myself, something more concrete than wanting to lose weight, will help my motivation to ride/swim/run.
I don't have to stay this way, overweight and uncomfortable, if I don't want to. I won't say "I can't run." anymore. I will say, "Running can be painful and possibly injurious right now, but I will run safely soon."
I also decided that I can overcome small obstacles, like ill-fitting pants, by doing the uncomfortable anyway. Becoming fit again isn't likely to be comfortable, and sitting on the couch wishing I could be fit certainly isn't comfortable.
Simple things to many of you out there, light bulb moment for me. I win.