The key to being a professional is about being where you said you would. Big show, dog and pony, county fair..... if you committed; you need to keep your word and be there.
No effort is ever wasted and sometimes we still have lessons in the art we haven't sold. Take the time and chance that you can apply new lessons to old images. If you ruin it, just let it go.
Seems like every where you turn, there are reasons to worry. Look for the positives in the world around you. Every cloud has a silver lining, sometimes it comes when you least expect it.