It sounds as though you certainly did the right thing by moving him out of the school in which he was having problems. Any time you have a teacher who doesn't listen to a parent (having 11 children by herself is not a good excuse) about anxiety shown by one of the children in her group, it is better to get the child out of the situation as quickly as possible. Willingness to comfort children is an essential attribute of a good teacher. And I wouldn't worry about whether your explanation about the move will make him expect something that drastic every time he has a problem in school. Young children tend to deal with one situation at a time. If he is happy in the new school, he will make satisfactory progress and give very little thought to why he was moved.
Our parenting advice is given as suggestions only. We recommend you also consult your healthcare provider, and urge you to contact them immediately if your question is urgent or about a medical condition.