Your mood is a follower, not a leader. Move first and watch it tag along.

Feeling usually arrives after action rather than before it, which is the opposite of how people schedule their lives. Waiting to feel like doing something can mean waiting indefinitely, because the motivation was going to be produced by starting. Movement generates the state you were waiting for.

On a flat day, pick the smallest physical first step and do it without negotiating: shoes on, page open, one rep. Give it ten minutes before judging whether you are up to it. The mood will usually have caught up by then, and if it has not, you still did ten minutes.