How do you know if your dog is pregnant?

Well, it's me again. I have a Lhasa Apso bitch. She was mated just 3 weeks ago and now we are wondering, how do we know if she's pregnant or not?
Some signs say that she is, because she has been sick in the morning, but she has also went off her food but is drinking a lot of water.

Any hints or suggestions?

Thanx!

I bred my bitch for the fiest ime recently, what I noticed was she seemed to go in a dreamlike mode was a little sick, but nothing to write home about, she just went softer somehow, then I noticed her shape was changing a little I had her scanned at home on day 28(heard that the stress of going to the vets to be scanned could cause obsorbsion of pups) so opted for it do be done at home, and have my "feeling" confirmed.

MO

i know my girl went off her food can't remember when though in relation to the mating

I got my girls scanned at 4 weeks just to make sure. Mine got morning sickness but didn't go off there food till the back end of their pregnacny.

at 3 weeks the puppy embryos will probably be about the size of a malteser, so it can be hard to tell if your bitch is pregant.
Early signs of pregancy can be a change in appetite, picky eating, being more "clingy" and affectionate and a slight swelling of the teats (particularly if its a first litter)

As her pregnancy goes on, you should be able to see obvious signs such as losing fur from the belly, teats enlarging and belly growing (this can be seen at around 5-6 weeks if its going to be a big litter.

Remember though that the signs of a phantom pregnancy are the same as a real pregnancy so I suppose if your really desperate to know, scanning is the best way, mind you I have bred a lot of litters, and i have never had a bitch scanned yet, I can usually tell to within a pup or two how many they are carrying by gentle palpation, (this is not advise unless you know what your doing) and so I never scan my bitches, I let nature take its course

When your bitch gets in to the later stages of pregancy she will need extra feeding, but split into smaller portions over the course of the day, and she may have a picky appetite, and require tempting with tasty foods. If your worried about anything at all, or in doubt about anything ask your vet, but try not to worry too much

Thanks for the responses
we took her to the vet and he said that it was a good sign that she was off her food. not so sure about that. we've started feeding her calcium too though because the stud dog owner had recommended it.
she's still been a little picky about her food. she won't eat, but she does drink a lot of water still.
she'll be four weeks this sunday coming.
I think they're due around April 16th, that is if she is pregnant.

mine never go off their grub..but they do become more affectionate ......one of mine goes all dreamy looking and it's then i normally know...but my other girl gives nothing away so i normally have her scanned at 28 days plus...good luck

hmmm we're starting to worry more
her sides are starting to clap in
we figure, the pups are absorbing what she IS eating
VET told us to get a syringe and to feed her that way, meaning she can't spit it out and both her and the pups are being fed.
we don't even know if there is any pups yet, but she never would go off her food. before we had her mated, she would eat anything and everything.
then a week in after the mating, she gets picky and barely eats anything....
just have to wait and see i guess.

Does the vet not want to see her?

My bitch had all the classic signs, and sadly was just fooling me.
Can you not get her scanned?