FWIW, I've been there too. One thing to realize is that action precedes motivation. The idea is to train yourself to do things you _don't_ want to do.

You have authority over your body. You can tell it to do things it doesn't want to.

You can walk into your bathroom and take a cold shower right now, on purpose. Your body doesn't want to, but it will yield if your mind tells it to.

In fact, doing that will switch up your state into a different one, which is half of the work needed to feel better.