I have a 2 week old chinese crested pup and she is not suckling very well and crying a fair bit. She is putting on weight but not as much as her 3 sisters. I wormed them today and she got a little less than a half a mil. She weighs 440 grams and the others weigh 480,500,and 520grams. She cries with a little shaky voice almost like she is having nightmares.Her skin appears to be hydrated, am I unnecessarily worrying or is she on her way to a downhill slide?
A very worried mum

Have you had the pups to the vet yet?
Being a bit smaller isn't always a problem, but the shakiness is.

How is her breathing? Does it sound rattley or wet, any mucous?
No problems with the palette?

Even if we could guess at what is wrong, I would suggest taking pup to the vet. Puppies can go from bad to worse in a matter of minutes. Is she the runt of the litter?