Kitten smells like poop

Alrighty, unsure if this is the right area of this forum, but I will post here and move later if need be.

So the deal is.. my 9 to 10 week old kitten smells of poop, and strongly. To the point where I can barely stand to be around her.

Some details 
- I am working new food into her diet, I buy more expensive natural "healthy" stuff. I started her on Iams kitten formula but she hated it and ate it begrudgingly and only when she was very hungry.  She is now eating a grain free brand of kibble and is entirely off the Iams, and she muches it down every morning. She gets soft food at night which I am slowly adding in new types to her diet as I have heard cats like variety. Only small portions of the new stuff, with the stuff she has already been eating.

- She had worms, after I got her and she just had her second de-worming pill this past Thursday. As well as some ear medications for mites.

- I see her cleaning her bum area often, as well as most of herself, she seems to pride herself in being clean.

- There looks to be no remnants of poo on her anywhere, yet the smell emanates from her bum area mostly.

- She has been having a bit of diarrhea the past couple days, I was attributing that to some new additions in food, as well as the de-worming medication she had Thursday..

-She doesn't seem to spend a whole bunch of time in the litterbox and I have been trying to clean the box every second day or so.

This is difficult as right now she really stinks and hanging around her is just gross. Especially when she wants to cuddle right now as the smell is stronger the closer you get to her.

Any ideas? I could take her to the vet, but I really do want to go, I have had her for two weeks and have already been twice, I'd really prefer not to have to again.

Someone recently posted a similar question about an adult cat: http://www.thecatsite.com/t/309344/cat-smells-like-poop

There's also this older post: http://www.thecatsite.com/t/187464/cat-smells-like-poo-but-no-visible-residue-help

The other thread has some suggestions, but I'll chime in that it could be something with the kitten's anal sacs (which smell horrible when there's a problem) - this would also make sense if she's cleaning her bum often. Most cats will try their best to eliminate the smell.  I know it's not exactly what you'd like to here, but I'd consider a vet trip. If she has an infection or and impacted anal gland, for instance, it's not going to get better without medication, and you shouldn't still be smelling it.

I agree that it could be an anal gland issue. My cat has had it twice now - the first time was a few days after I brought her home (they were just full), and the second time they became impacted because I didn't take her to the vet fast enough. Both times she smelled stinky, and she licked her butt a lot to try to get rid of the smell. Luckily it's a really easy thing for the vet to express the glands, so don't wait to go like I did!