The problem is that I have evidence to the contrary. I have already started wasting time and not doing anything worthwhile.
In any case, I don't see myself doing anything other than programming for a career, though I ought to take some time to explore as well.
Collapsing is a natural reaction to the removal of pressure. You have spent a long time trying to do work that you didn't want to do. The corporate experience trains you to believe that you are naturally lazy, because you spend all day in agonized revulsion against the productive, useful work you are asked to do. The secret is that just because you do not want to do certain work for certain people does not mean you are lazy.
Other people have been in control of your productivity for a long time, and your only freedom was to resist, shut down, and be lazy. You need to indulge that until you feel completely reassured that you are free and in control of your own life. Then your own tendencies will come out, and I guarantee you that what little I know about you from your question (specifically, that you have skills that took a lot of time and unwitting dedication to develop, and that you worry about what you might or might not accomplish) is enough to know that you will be happiest doing productive work.