I have found that motivation comes after the doing, not before, especially when one is depressed or anxious. I have to make myself try some things and if I find something I enjoy, then the motivation is there to continue.

So, the hard part is going ahead and trying something, even if you aren't "feeling it". Start with an activity you think you have at least some interest in. If you give it a good shot and are still not enjoying it, give yourself permission to move on to something else. Eventually you'll land on something that is right for you.