I have had this happen more than a few times to me, at least being inspired and thinking "I'm gonna create a comic, I can do a story now!" and then a little bit in finding myself able to do no such thing. I work as a professional, so I have to agree that it isn't about inspiration when you're producing; inspiration is one of those things that's nice to have...as long as it's directed where you want it, which it rarely ever is.
My advice is, if you feel strongly inspired by something, first spend a while developing any potential story. Figure out where the story can go, where you want it to go, what you want to do with it...do some sketches of characters and develop them. Develop them to distinguish them from the source of your inspiration, so that they are characters that are distinct. The practice will also make it easier for you to draw them. Muscle memory is a part of art, and once you've drawn a character enough times, they become almost like a reflex.
The time you've spent doing this, developing the story and characters, can help you decide if you're really interested in doing that story. It also forces you to wait before tackling the main project and organize it a bit better, so if you do end up going on and doing it, you'll have an easier time and sure footing.
Even if you decide not to do the brainstorming, sketching, and organization, I still advise this above all: wait. Give it a week or two. If after that time you still feel like you want to do it, then go for it -- you're probably dedicated enough to it and it isn't just a momentary fascination. But usually trying to do stories right when they hit you...that doesn't end well. That momentary enthusiasm dissipates awfully fast, I'm sorry to say.
Last of all, I'd like to add: don't get rid of the pages that you work on. Don't get rid of the sketches or anything else. Keep the files and look them over later on, because sometimes they can inspire something better. My current project is something that had two or three previous forms, each with several pages completely produced before I decided to set it aside until I could develop it to something more workable. It took months of walking away and coming back, but eventually I did decide I was up for the task and committed to it, and now I have half a year's worth of comics waiting to be posted, with more produced every week.
Good luck and I hope this helps!