I'm sorry you had that experience. When T1 was pregnant she wouldn't stop yawning in our sessions. It made me feel like I was boring her, but when I asked her, she said she hadn't even realize she was doing it and that it was because she was tired.
Whatever the reason is, it's definitely not your fault. Everyone can have a bad day or be more tired some days, but if it keeps happening I think it is disrespectful and unprofessional of them. I would bring it up in the next session