People will try to find motivational speech to use to encourage you and that’s not bad at all but to be honest with you, I'd tell you to take a break, don't worry about it. And do something else. If you force yourself it won't happen and you will end up being frustrated even more and this is why.
I was in the same boat as you. It’s important to remember the reasons why you started and the reasons why you do it. If those reasons aren't as important any more or not there for any reason it will be hard to push yourself.
Another thing is that, its okay to take a break, its okay to step away and not do it for a while. Then once you are ready and have had enough time to rest TRUST me, if it is your passion, it will eventually draw you back in. I have been though what you are going through and that’s what worked for me.
Remember. This is supposed to be for fun. Its not like you make a living form it. it does not pay your bills so do take and enjoy the break. During that break, join forums, go on events, Go se a movie, hang out with friends, find things that will inspire you to come up with fresh ideas so you can come back to your art.
Another thing is that people underestimate the amount of time they goes into creating art. It’s not a joke and its not easy, you have to really love it. anyway, thats all I've got for you. stay strong.