I think that two of the most common misconceptions about addiction are:

a.) it *always* leads to poverty, homelessness, joblessness, or to any other degree of not being able to function. (it didn't for me, although it certainly would have gone that way at the rate I was going.)
b.) addicts use every single day. (not always the case.)

ultimately, only you can say whether or not you're an addict.