Here are some things to consider.
Yes get mad, in a healthy way. I don't mean for you to start throwing things around. I mean get up and start taking action. Sometimes it's a depressed state of mind that has us thinking that we can't play what we want, or that we aren't good enough. It's simply not true. The truth is we can play exactly what we want if we keep pushing forward. It won't come easy. Getting angry in a healthy way, not in a destructive way can help you get past some of the stuff that's been holding you back. Olympians are sometimes trained to get mad as a psychological technique to stand strong in the face of adversity such as in the violent environment of competition. Football players get angry all the time. And so do rugby players. You can use anger in a healthy way and can be very effective. It's really ok to get mad. Don't overdo it or hurt anyone in the process and you'll be ok. So get up, get mad and try it again and again until you get it right. Pick up your guitar and start playing that thing.
Crank it UP!
Listen to your favorite music. We can get lost in a bunch of music that is not really moving us a hundred percent. I believe the trick is that you have to keep seeking those bands or musicians that really make you go wow that was insane! We can't be passive about it we must be proactive. This seems like it would be common sense but in the everyday hustle of life sometimes we can forget to listen to those CD's that really get us going. What would really be nice is to feel on fire all the time but life things get in the way and we should have our favorite music nearby when our inspiration starts to dwindle and the fire starts to burn out. So crank it up!
Write a Goal Down
This is much simpler than it actually sounds. For example, a goal can be epic, something that won't get done for more than ten years, or it can be something as simple as getting one song done. In other words, finish it. You started it now get it done. Another goal can be to record some of your ideas. Recording will really tell you what you need to work on and can be really fun to listen to. You might end up listening to it for several days in a row and this can really keep you inspired. I do this all the time and it works like a charm. The hard part is recording it. You can then burn a CD or put it on your phone and listen to it while you drive to work or while you're working out. Having little goals can spawn greater goals and can boost your confidence so much that you get used to hitting goals. The more goals you hit, the better and more confident you feel. The better you feel, the better your playing will be.
Learn Something New
Take another lesson. Buy an instructional product online or at the store. Look for a new lick. Try to play a scale you barely ever use. All of these things can be little triggers that can spark an afternoon of playing, or even an all night session for us vampires. Maybe the backing tracks you are using, you've already burned through them, buy new ones, or look for new ones online.
Watch your favorite player on YouTube
The other day I watched Paul Gilbert and in his video he was giving examples of things you can do with rhythm. This immediately translated into a new riff. Sometimes it's all you need. The trick is to keep searching, keep seeking until something triggers your emotions and gets you up off the chair and plugged into your amp.
Get away and go do something fun. Get your mind totally off of music and your guitar for a good while and do something that is totally unrelated like a movie or hanging out with your non-musical friends, or even your family. It can be anything really. When you come back your mind will be fresh and ready to rip into some scorching lead or some funky blues rhythm or whatever it is that you play. You'll be re-energized. Your battery will be charged and when you are in this state you are highly likely to be exceptionally efficient. Working out is one of the best ways to do this but it's only one way.
P.S. Try at least one of these things today, don't wait, you are reading it for a reason. If you needed one, here it is. There are several things mentioned above. If one doesn't work, try the other. Keep trying. Keep playing and I hope that I have led you to something that will get you up and going again. Don't cheat the world of your music. There's somebody out there that needs to hear it.
I am a guitar player, songwriter and instructor. Check out my band site Spice up your songs with a free progression book