The easiest way to deal with it is to just put it aside until you get the urge again. Could be a week, a month. a year... whatever, but if you like building model kits, the urge will come back. Until it does, don't worry about it. The "problem" will solve itself.
There's nothing worse that forcing yourself to build a model. At that point it goes from "hobby" to "work," and that defeats the whole purpose. Let it go until the urge comes back.