My cat got outside now she won't come out of her litter box

My cat got outside last night, which isnt so unusual execpt this morning was yard day. and she is usually only outside for an hour or 2. She came in and had this weird meow then growled a little at the other cats, then went in her box. she came out once for a brief time. i picked her up and when i did she had a deep internal growling and was pretty limp. she is drooling a bit as well. i want to think this all due to the shock of being outside for the length that she was outside. but i'm afraid it could be more. 

Thoughts please!

I would be concerned enough to take her to the vet, if I were you.

Is she spayed?

Yes she is spayed and utd on her shots

She is now out of her litter box, but hiding under one of the beds.

It still sounds like she should see a vet

what do you mean by "yard day"??

They were cutting the grass, landscaping. We live in a townhouse community

Do they spray chemicals?

No just lots of very loud noises. And big machines with blades. She isn't hurt that I can see, just extremely shook

yup, t.peanut--the chemicals is exactly why i asked.  hasianC.lady--even if your place didn't spray lawn chemicals, i'd check to see if any yards around you were recently treated.  i believe they're required to put little flags in the yards when they do it.

even if there isn't any sign of chemical application, unless your girl is now acting 'normal,' i think she got into something while outside.  she had quite a bit of time to roam around, and there's a number of things that could be present--pesticides/insecticides that someone put on their landscaping plants or around their foundation, plants themselves that can be poisonous to cats (are there any lilies around?), cleaning solvents (maybe someone cleaned their grill, etc...), antifreeze, rat/mole poison....there's a lot.  especially if she might have gotten inside someone's garage or shed.

i don't want to be polly-alarmist, but the facts that 1)she's withdrawn and anxious, 2)when you picked her up she growled (possibly an indication of abdominal pain), and 3)she's DROOLING, make me wonder.

i HOPE she's okay.  but i wanted to make sure you considered these possibilities in case she doesn't "snap out of it."

She is begining to snap out of it today. This morning when I woke up I went to check on her and she was out from under the bed. I did a few things and she came out of that room and into mine. She did venture into the litter box again for a brief stay, but she came out and had some water. Then went potty and covered it. When I left for work she was sitting on my dresser cleaning herself.
I think these are all good signs. Oh and when I picked her she didn't growl or show

i'm glad to hear that things got better!  i can't get out here every day, but i've been thinking about your kitty.  i hope she's still doing okay.