KayAnn I think Liz may be onto something. It could be related to the popping sounds. I don't think it sounds like Lyme at this point because Bella never once put her leg down once she started limping until after we saw the vet and she was 2 days or so into her antibiotic. (((more hugs to you both)))

PS - I could be wrong, but I think Advantage only kills fleas and not ticks. At any rate, I am glad that tomorrow is almost here so you will get some answers and she'll be on the road to recovery ASAP.