accidental pregnancy,please help

Hi there,

I have a female shitzu x Australian terrier, she got knotted around 6 weeks ago about 8 times, When I got her 5 months ago the previous owner told me she was spayed, so didn't think anything of it, until she went on heat, and by the time I had noticed they were already knotted in the back yard, that went on for around 25 minutes or more I tried to keep them separated but not allowed dogs in the house, so when ever I went out I came home to find them knotted AGAIN , I am not a BYB as this was accidental, she has been to the vet 3 weeks ago as she ate a poison bait that was found under the house, the vet did an xray and said that she had some fluid which suggested she was pregnant but could see any skeletons as was too soon, she then went back 3 days later due to constipation, and another vet said she was pregnant,

but she isn't showing, and she has clear liquid coming out of her nipples, she has been sleeping in laundry or bathroom on piles of clothes, I have noticed she is trying hang around me more often and even jumping on my lap which she never does, but then she is still running around a playing like a 12 week old puppy,

how do I know for sure she is pregnant with out going to vet ? nearest vet is 1.5 hours away, and when will her belly start big? her ribs are a little bigger but not enough to think she is pregnant, the only signs she is showing is that she has bigger nipples with clear liquid coming out when i squeeze.


ps she mated with a maltese