Please come back and tell us whether you are still getting this problem in another week in the same way.
I have to say that it is NOT common at all to get a fever after class. Your body is an expert at dealing with the incredible inputs you encounter on a day by day and moment by moment basis. If you are well hydrated and well nourished are not immunologically suppressed, if your studio is not too hot and the conditions are optimum then your reactions are very odd indeed.
What can you say about the temperatures in the studio itself? How long are you staying in Savasana afterwards? What do you do after class? Where do you go, what do you eat, what is the first sign that something is not right? Anything you can think of. Work through the moments after class. What would happen for example if next time you went to class and you just stayed in the room and didn’t participate? Lots of things coming to mind that we can explore. Get back to me after you’ve had a moment to reflect.