can someone please help

Okay so i have a problem. i have/ had a best friend who was always sad and like her personal life was really bad and  she never had anyone except me i was always there for her because she had no one but me. but now she made new friends and she's really happy and she totally forgot about me, she doesn't even talk to me. I've texted her but she doesn't reply. did i do something wrong? do i stop trying?