I have problems with that too-- and sometimes I find that it's my imagination that actually saves me. If I can get up the energy to imagine something super epic, it gives me what I need.
Also, validating small steps in yourself. For instance, I may not have made it to tai chi in time the other day, but I got up and got ready! LIKE A BOSS
If you give yourself a little mental soundtrack when you're listless, sometimes it can help pick you up. I've got a few go-to songs I'll be happy to share when I can post links