I've been there Tom, and I think your fundamental problem is sleep deprivation. I know you said you can't stop working shifts, but have you thought about stopping working shifts and getting another, entirely different part time job that you do almost for fun (but not quite because you would need the money) on, say, Friday evenings or Saturday mornings or whenever you have a free slot. That would solve your problem of lack of sleep because you'd have regular bed times, you would have enought money because of job 2, and job 2 would also provide the new interest that you feel the lack of at the moment.