I just had to comment on this especially after seeing the other responses. Several moms say that they get this after the second pregnancy... Well, ME TOO! I don't know if it is a coincidence or what, but worth pointing out. But seriously, it took me forever to want to have sex after my second was born- beyond 11 months at least. We did end up having sex throughout that time, and I did find that eventually it helped me actually WANT to do it...
I know it happens to a lot of moms- I don't know if that means that it is okay, or if it is actually a problem that should be addressed. It wouldn't hurt to speak to a doctor, though. If you choose to not talk to a doctor, give it a little more time. You are definitely in the normal range. I never seeked medical advice at the time of my low libido, though. Now (pretty much ever since I got pregnant with my third), I'm totally myself again- even now when I'm so super uncomfortably pregnant again.
I don't think that the fact that there are five kids between the two of you makes a difference in the lack of interest on your part... something like that can definitely be distracting, but you would know if otherwise you wanted to without the kiddies being a factor.
Also- I notice that the longer my husband are together (we've been together for almost 8 years), the less we "make-out"... But when we do now it REALLY sparks up things!!! If it isn't "making-out" for you two, it just could be something else... Just an idea.