Do a little bit.
Just a little. You don't have to stay up late. Just commit an empty file. Fix a typo. Write one test. Create a branch.
Do one, small thing to change your state. Lay the next stepping stone in the path. You don't need to finish, as long as what you leave there points the direction you want to go.
With side projects often comes guilt. Many days you're tempted to do nothing because what you have time for won't be "enough". But you don't need to tackle big things every day to make progress. "Enough" velocity is anything that you have time for.
So just do a little, tiny thing. One baby step. Then go to sleep. Take another tomorrow.