Oh, I know that feeling. Non-inspirational, I mean. I used to have this problem from time to time... But, I'll give you a hand, there is a way out. When I have inspirational moments I draw a lot of concepts, and when I have no inspiration I'm working on those concepts. It's almost no need to be super-creative here, if you for instance drawing hairs or... buttons... it's really a matter of just having your butt on the chair and working. I listen the music during this moments... And the truth is that on the real work you have to do much more exactly this work. Drawing with inspiration is good for the beginning of the work. Just try to collect as many sketches and ideas, while you are inspired, so that you can use them later. Plus, the more experience you get, the less inspiration you need. In my humble opinion inspiration makes a hard work easy, so if you practice more, there will be no hard things for you... or in other words, inspiration won't affect your drawing life so badly. )))