First, why don't you just tell her thanks for the gift, but you need some time away from them to sort yourself out. Or just don't contact them at all.
Second, what your mom and dad do or don't do or what they say about you - you have no control over that.
Third, take some time for yourself and get some help. I feel bad for the pain you are going through, but you need to take care of yourself. If they upset you so much you really need to talk to someone in confidence who is trained to help you through this type of stuff. There is a way out. You don't have to be this unhappy.