Possibly pregnant lab

Question
I have a lab that is about 1 year and 5 months old.  I was not planning on breeding her yet, but another family member left my female and male in the yard together.  Here we are about 6 weeks later, and she is definitely showing signs of pregnancy.  She is a thin dog (she has been her whole life), but lately her tummy has been growing.  At first she looked chubby, but now her tummy has been drooping a little.  It's not huge, but it's definitely bigger that it used to be.  Her nipples are also very swollen, but nothing is coming out of them (yet anyway).  Her appetite has increased quite a bit, but at the end of her heat cycle and maybe a little after, she hardly ate at all.  She loves playing with the ball, and will still play all day if you let her, but she gets tired easier (which still doesn't stop her), and she is much slower than she was.  She is moody toward my male dog (such as if he wants to play rough with her she growls at him).  

I took her to the vet today and he felt around her stomach and said he couldn't feel anything.  He said that she may or may not be pregnant, but would lean more towards yes.  We are scheduled to do an X-ray next week, but I need to know as soon as possible if she is pregnant.  I don't want to spend all the money to prepare and her not whelping puppies, but I don't want to wait much longer to get her area set up if she is pregnant.  

In your opinion, what do you think?  Do you think she is, or not?  I know you are not a vet, and I know you can't see her, but just from your experience what do you think?  If she was really pregnant, wouldn't we be able to feel the puppies??  I mean if she was pregnant, then she would only have another 2/3 weeks tops left.  Any and all help is much appreciated.

Thanks

Answer
At 30 days post breeding, your vet should be able to do 1 of 2 things (or both).  Most vets have ultrasound machines in their offices, and can do one to see pups.  Even when they are not fully developed, at 30 days (1/2 way through gestation) heartbeats should be easily seen on the screen, even a rough count of pups is possible.  The other is a Relaxin test, which is a pregnancy test.  I don't know how they do it, I think it's a blood test, but if you ask about it, they should know what you are talking about.  These 2 ways will CONFIRM pregnancy.  

I would not do an xray at this point.  6 weeks into the gestation, the little bodies won't be calcified enough to really show on an xray.  We normally do an xray a few days before the anticipated whelp date so that we can get a good count on pups, to know how manyt to expect.  

A false pregnancy is very possible as well.  They will show all the signs of pregnancy, including weight gain, swelling nipples, and even producing milk.  

This is a great website for information....
Here is the link to the section about "Signs of Pregnancy":
http://www.debbiejensen.com/signs_of_pregnant.html

If you look on the left side, there are all sorts of really great topics to help you prepare if your girl is indeed pregnany.