(Also worth noting that this isn't particularly bad, in the grand scheme of things. When you are dejected the rose colored glasses come off -- so if you want to keep motivated, build that emotion from reasons that are true even when the alternatives seem quite good.)
A side project doesn't need to be profitable, or an actual business. It can be anything you want to do as a hobby.
Actually, I kind of like doing just that and leaving 4 pm sharp :)