I'm sorry no one has felt able to comment. Thursday is tomorrow, did you go to another Vet after all? I don't suppose there is any point in guessing if she was spayed improperly, what you need is to know for sure. Though I guess it's a possiblity, so might other things be a possiblity. Sorry, that's an absolutely useless answer but you really need your/a Vet to talk to.
Please let us know the outcome. We may not be able to help but we certainly are concerned and hope it works out satisfactorily. Poor little girlypup, hope she's OK.