This is common, when you work at the same thing as your hobby, I Used to be in those shoes as well, i have a few different ways of just Getting urge to Draw something again.

this is a fun interesting one. go Outside and Take a few pictures of Clouds. that look like things put them on your computer Open them up in your Art Program put a Layer on top of them and begin to Draw what you see in them. it is a Great Exercise not only does it test your perspectives but it also challenges your imagination
Example http://www.furaffinity.net/view/20530250/ by Tallpaulky

Another one that is a REAL motivation supply resource is Streaming, you tend to just keep Going when you have People streaming with you. especially if they are Active!

you can Ask people to Share Ideas with you, no obligations but it is always Fun to hear what people think would look good in your style =3

This sounds like fun and I think i should try this :)

I know what you mean. I have found my motivation to be fleeting. I try to find it again through music, cartoons, nostalgia, and talking with friends. I get a lot of ideas from friends and even asked them for prompts to help be get drawing.  thecruelseasons has been great at giving me ideas, and we bounce ideas off of each other. It has helped me keep drawing and practicing with regularity.

I don't know, I just do random doodles while watching or listening to something and ideas form. Kinda right now I was doodling legend of zelda music and thought of creating a demon lord OC!

When I can't focus anymore it helps me to get out and do something else for a while. Having a full-time job that I like helps in that regard, but so do video games, watching a show on TV, going for a walk, etc.

This is what i do most of the time. Playing video games and watching tv but sometimes at the end of the day it feels like some kind of waste of time because I could have done other things instead of this

I usually just do sketches if I can't be bothered to do a full product.

das wird schon