heat cycle aftr whelping

Question
our lab just had her first litter of puppies, 11 to be exact. they are 11 weeks old, I called and asked our trusty vet "how long till she comes back into heat" so that I knew approximately how long I had to get her in in to be spayed, they informed me 4-6 months from last heat. SURPRISE SURPRISE the vet informs me that she was "PREGNANT" when they did the procedure.. 11 puppies to be exact. Is this AT ALL POSSIBLY? Wouldn't the 11 puppies the vet "claimed to be" puppies actually be the scar tissue/nodules(sorry don't the exact term for that) where the last 11 puppies were attached to mama dog being only 11 weeks from whelping, wouldn't it still be apparently fresh looking and possibly be mistaken as puppies?

Answer
Wow, 11 seems to be the lucky number here. If you took mom in to be spayed 11 weeks after she gave birth to the last litter, it would suprise me that she was pregnant this soon. I would definitely call the vet and talk to them about this. This is odd. I'm not saying that it couldn't happen, was there any way that she could have been in heat and you missed it? And does she have access to a male dog?

As for the scar tissue theory, there's a definate difference between scar tissue and puppies. The uterus should have been healed by 11 weeks, I really don't think that the vet could have mistaken scar tissue for puppies. The puppies would have been little balls in the uterus, scar tissue looks different. Like I said, this one is odd, has me stumped. The only advice I can give you is to talk to your vet about it. You can also ask the other expert here if they had ever seen anything like this. Either way, I wish you good luck.