I'm sorry, but I have to agree with megansmomma. This little girl should have been spayed immediately after she had the first puppy, and lost her, and her back legs were giving out during her pregnancy.
She's 2 and 1/2 years old. She should have been spayed a long time ago, if the OP truly didn't intend to breed her again. Each heat she has gone through exposed her to more estrogen and increased her risk of cancer.
1st time, yes, an accident. 2nd time, pure negligence on the OP's part.
And you most certainly don't leave an unspayed female with an intact male.
Believe me, I know, because I am living next door to 7 Poodles, who's owners thought their male couldn't get to their female, if they kept panties on her.
Perhaps, if you were involved in Rescue, as megansmomma is, you would have a different perspective.
My sympathy lies with this poor little dog, and the puppies.