not a good situation

little air filter problem

about 3 weeks ago I cleaned and oiled the K&N filter i had on my cold air system. about 2 weeks ago my 99 GT started idling poorly sometimes but not always. this weekend i finally discovered that the air filter had actually FALLEN OFF (oh crap) and that i had been driving without one for about 2 weeks. This is not a good situation, especially because i live on a dirt road. my question is: is this something that will destroy my engine sooner or later due to all the dirt that must have been sucked in, and is it imperative that i have to clean the internals soon, or if i havent destroyed my engine yet, just put on a new filter and go with it? also, if i have to clean out the engine is there a way to do it without taking it all apart? thanks for any info you can give me.