My bitch is 5 weeks gone and everything is going to plan so far. Fingers crossed. But in the last few days she has started to drink twice as much as usual. Is this normal?
She has expanded alot over the last few days, even though the scan last week only showed 3 pups, she is a small dog so small litter was expected.
Thanks

Personally not wanting to alarm or anything I would get her to the vets asap.

Just get her checked out, excessive drinking and urinating(Making that assumption here) is a classic symptom of Pyometra, the sooner you catch that the better(Ie get to the vets now).

Ask them to do a white blood cell count, and tell them about her symptoms.

polydypsia(excessive drinking) can be associated with a miriad of other problems and it might just be a symptom of the pregancy but personally I would get her to the vets asap!.