Consider taking a break for a week or two?

Every year in December, I put the comic into what I call a "half-hibernation", where I update only once a week. This year, I'm likely to put the comic on full hibernation during that month while I prepare for the next year, and include sketches and 3D models. Last year I tried to make lots of changes to the Ook Island model, but the half-hibernation really only frees up enough time for the Christmas stuff I have to do each year. This December, I have a lot of stuff to prepare for the next year of comics, including a site redesign and HOPEFULLY 3D characters. Last year, that half-hibernation wasn't enough to make all the updates to the Ook Island model that I wanted.
I'm also going to the F3 furry convention in Springfield, MO on either Dec 14 or 15, and I have to adjust my sleep schedule so that I can stay awake for all of the day's events. ALL... DAY. This is currently my biggest motivator for changing my sleep schedule.

I am just concerned that you push yourself for the comic too much. A couple times fairly recently it's started to get a bit dry and uninteresting, and most importantly unfunny. While someone else could point these things out and cry for you to stop wasting space and just quit the comic entirely, I'm not going to be like that because it was genuinely funny at some point. Yes, during Ferrets Vs. Lemmings.
The reason why I say you should take a break from the comic is so that you can back away from the comic for a bit, open up to the outside world a little bit, and not fret about rushing yet another deadline (in effect, making the comic bad). Relax. Maybe get some fresh ideas. When the comic returns, chances are it's going to recapture that magic with you fully rejuvenated and not rushing yourself.
Even after this break, though, I highly suggest you just switch to one comic a week.
Regarding 3D models for your characters? I REALLY don't like this idea. Once again I'm going to blame your tireless work on the comic finally wearing down on you if you thought your drawings were starting to degrade. If I can swing time I could actually offer to run a guest comic or two (for free, even though I'm in commission mode) if I'm given a script within a week. I'm not participating in Second Life anymore, though, so my backgrounds may wind up being drawn or Doom-rendered instead (the former more likely).

Right now, my goal is to finish the current storyline(which admittedly isn't very planned-out, except the ending) the Monday before Thanksgiving. Then I take my month-long break(as usual, except with no comics at all). I'm working on some things to make the comic more fun for both me and my readers next year, namely, doing a different comic set in TODAY's time and only doing Kenny comics as special stories, posting only after the entire story is finished. The Halloween comic I posted just now is a rough example of what I plan. I can do SKYRIM JOKES with my Ferret Williams comics!

The reason I'd like to do 3D models for the characters is actually for time-saving. My process has me setting up a 3D scene, rendering a complete 3D scene, AND THEN drawing characters into it, followed by trying to match the lighting on the shading. Once a character's model is built(yeah, that's the big time-hog), I can skip the drawing, coloring and shading steps. In addition, I can do ANIMATIONS! Oh, AND I'll never again forget to color Fuego's eyes, LOL! I plan on building a 3D model for my Ferret Williams comics, too, but I'm still likely to do those comics completely black and white, judging by how fast today's comic was to draw, and how it doesn't need 3D at all. The 3D model of Ferret Williams(or Ferret-Garrett?) will be used for reference and ESPECIALLY for animated cartoons. No set schedule for animated cartoons, and when they post, they'll be THE post for the day, instead of in addition to the comic.

Basically, I'm spreading the comic site's focus wider so that I don't limit myself too much & can do a wider variety of things. Maybe even, dare I suggest it... games? Having quicker comics will free up a lot of time for things like that. Mostly, though, quicker comics will prevent them from keeping me up late, because even if I wait until the last minute(again), the comic will only take 2 hours.

As for the comic getting less funny, I agree. A story can only be funny if the author is also having fun with it, and I'm torturing myself with it(Cue the "You're doing it wrong!" meme). However, I'd also like to complete Ferrets Vs Lemmings with a complete storyline that finally has something to do with the title. Ferrets Vs Lemmings was meant to give direction to the comic, but it seems that direction also brings with it the fact that it works best in standalone stories rather than a continuous storyline. I have 2 stories planned that I intend to take my time on.

And the sleep I've gotten the last 2 nights? Magnificent. I woke up at 8am, and I plan on doing that again tonight. Hopefully I can get Thursday's comic done in the daytime as a result.

Good luck, then. Just don't push yourself or the comic too hard. I really don't want this thing to fall under.