I would get her to a vet asap. The bubbles you saw were probably from mucus from an infection. I rescued a snake with a severe RI and can tell you that bubbles/ strings of mucus when she yawns are a red flag! If you suspect she has an RI, because of the breathing you should take her to a vet anyway because they usually do not get better on their own. I would make a vet apointment as soon as you can to get her on some meds. I'm glad she's in a good home now! Good luck with her.