Stranger Anxiety? Again?

So, I have been racking my brain trying to come up with a reason Sissy did not want to go to Bible class and was so awful. Was she tired and/or sick (she did sleep a lot when we got home and for the next 2 days after that), is she teething (we have the bottom 2 year molars, but not the top and she would not dare let me check for them saying "Teefies ok")...what is wrong? She has never acted that way before!
Well, I am glancing through one of the parents magazines I never have time to read and it says something about Toddlers and stranger anxiety and how they can still go through it at this age too. Ah ha...maybe that's it!
She is definitely my sensitive child. Overly sensitive! And does not like for me to leave to go anywhere unless daddy is here. I usually don't go places without them because of his work schedule (read: 18+ hours a day) and my mom has my grandparents to take care of these days...so life without the kiddos is virtually never. We have had a few visitors this week and she has clinged to me saying "Mommy go doctor?" (like I am going to leave her with them...I went to the doc last week) Even when my mom has come over lately, she hasn't necessarily wanted me to leave. Hmmm.
She has gone through SA many times in her short 2 years and I would say never really got through it totally. I really want an explanation for this behavior...I don't want people to label her as a bad child by any means because she has always been so easy and good.
She did bring up bible class today and we talked about it a little. She said she would sit in Ms. Lori's lap until mommy comes back to get her. We will see.
Oh, and a funny one...last night when we were saying prayers, I said "God, please help Sissy not throw fits" and she finished the sentence with "in Bible Class. Amen. Good Job."