How to know before hand that a female dog will have her pups?

My female dog is huge and has been acting somewhat weird and her nibbles are huge and milk is coming out what should I do and how long before she has her little puppys. Its a Chihuahua dog

She could be lactating or pregnant(depending on her activities with other dogs.) if she is pregnant, the pups could be expected within 21 weeks or so...

You should know this stuff BEFORE you breed your dog/let your unspayed dog roam aroundGood job BYB

WELL CLUELESS BACKYARD BREEDER NOW IS A GREAT TIME TO CALL YOUR VET ....SOMETHING YOU SHOULD HAVE DONE ALLREADY....... CHIHUAHUAS NEED A C SECTION 90% OF THE TIME.... HOPE YOU HAVE $1200 TO $1700 ON HAND FOR THAT .

STOP BREEDING U IMATURE CHILD!!! ALMOST ALL OF UR LITTER WILL END UP IN A POUND AND KILLED!!! WE DON'T NEED ANYMORE DOGS IN THIS WORLD

21 weeks?! LMAO dogs are only pregnant for 9 weeks exactly (Give or take a day) If she has milk already then it will be VERY soon! Is she nesting? Make a nesting box with lots of warm blankets and some where quiet. Call a vet and speak with them its free to at least speak with them. Did a larger dog get her pregnant? She may need a c-section if so and sometimes they wont it just depends on the dogs size etc. Stay calm if you panic the dog will panic as well. Once the puppys are born wash your hands before you handle them and dont let strangers pet or play with them as they can get sick until first set of shots. I do hope you find good homes for them since she is small she wont have that many puppies. My pomeranian is 4 lbs and she had 2 stillborns and 1 that lived. I pray for a save birthing!