I know what u mean, its like some days u have the feelin that you can play really good and u can, and some days, its like your **** and u just cant get any feeling into your playing. All I can suggest is that you should practice your technique and scales so that you dont even have to think about it, just make sure you really know it. And If struggle playing the harder stuff in fornt of people play some eayser stuff and then work on improving. You should try some slower stuff like santana and improvise more, people will still think its good. At the end of the day what average person can tell the differnce in skill between 2 finger tapping and sweeped appegios.