Good Morning and welcome! I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
Poor little Bella could certianly be pregnant. If she was in the Estrus part of her cycle, this is when she is receptive and will allow the males to breed her. It also may be that Bella is showing a false pregnancy. In this case, she will follow all the signs of being pregnant until day 70 of her gestation period. The normal gestation period is 65 days. It is best, at this time, to have Bella Ultrasounded since pregnancy can be determined after 21 days and if she is, you will have to allow her to have the puppies since we have no safe way to abort them.
If she has a false pregnancy, this will all resolve after 70 days.These signs you are seeing are typical for hormonal chnages but this can be pregnancy or a false pregnancy...no way to tell for sure without an xray or Ultrasound.
Does that make sense to you?
Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please REPLY so I can clarify for you.
Sincerely, Dr. Loretta