You build a growing list of things you know. Then you simply put them together in different ways, and add your own slant where it fits.

I like the jam tracks myself. I play what licks I have learned so far and try doing them in different ways, maybe not exactly as I've heard. Sometimes try adding in new bits that I make up. Some don't work, so I wait until the part comes around again and try it differently.

That's really when I have some of my most fun is just jamming to the tracks and letting loose.

I can definitely relate to what you are saying. Sometimes I have an off day and I'm almost angry when I shut off my amp. I know I'm must having an off day, but knowing doesn't leave me less frustrated. On the other hand, some days I am "in the zone". Not all my combos are coming out great, but I'm starting to have periods when I'm just feeling relaxed and everything is just where it's supposed to be and it feels effortless.

Don't get me wrong: I'm just learning so this is a pretty random thing and doesn't last long, but it gives me great hope!

Hang in there, dude. I keep remembering what somebody posted about the jazz master that only had 2 fingers. Inspiration for sure!