Very unhappy head of hair

Hi, My name is Brigitte and I am new to this forum.  I'm experiencing a problem I could really use some feedback on.   Today I have a gold, brassy,head of hair.  This was done in a beauty school, where they did a great job the last time I was there.  I don't know how to eliminate the gold.  I have always had highlighted and lowlighted hair, at least until now, and I just want to look like myself again.  Does anyone know what I can do to reduce the gold at least temporarily?  There's been so much chemical processing going on in my hair, that I am reluctant to do anything but I feel I cannot go anywhere without a hat.  Going to a salon is out of the question, at least for now.  Thank you for any help you can offer.

You don't have to go brown if you don't want to.  Any chance you can go back to the beauty school and ask them to put a violet based color over it?  Violet will tone down the yellow and make you closer to a medium or ash blonde.