I'm sorry you are going through this and I understand how stressful and frustrating it can be when your baby is sick. It seems you have a very caring vet, because if it was all about the money they would just keep spinning the wheels to get more $$$ out of you. Her sending you to get a second opinion just goes to show you how much she truly does care. Please do as advised and maybe a new set of eyes will see something that was overlooked.  
Hope everything goes well and I pray your baby recoverys quickly. 
