How safe is taking Levyothyroxine for Hashimoto disease?

my daughter was recently diagnosed with Hashimoto disease. She was on levyothyroxine 50 MCG which she was taken off one month ago. The past few days she has been having a lot of anxiety and she says sometimes it is hard to breath as she feels her throat is going to close. She has contacted her doctor but the doctor will not be in until Friday. My daughter's behavior is clearly upset, she is pacing and continuously says she is filled with anxiety and cannot hold still. Not certain what to do as I have never seen this behavior in her. She is 21 years old