Does she have parvo again?

My pup just got out the vet. she was there for 6 days and i have a follow up visit today. Before i was about to take her, she threw up the same yellow foamy stuff again!!! is it likey that she can catch it again within a couple of days with her being OUT the vet. I disinfected the house and threw away her old bowl and toys. i just noticed her stomach is a little bigger too. I havent seen her mating with any dogs while she was with me. is it possible that she may be pregnant and just throwing up or??? help me out people!! please