Diagnosis?

hi everyone! i’m looking for some advice. i’m 20 years old. i’ve thought for some time now that i have autism. i’ve got a long list of how i acted as a child and how i act now. i phoned my gp a couple times and even had an appointment to discuss this. as usual, i was turned away from a diagnosis and told to seek help elsewhere, specifically here. i believe a diagnosis would really help me and stop my constant questioning of myself. i was always the ‘well-behaved smart girl’ in school, and i am currently doing well in university, which is why i think no one has taken me seriously. the reality is, i have struggled so much with what i’ve discovered is called ‘masking’. i never realised that neurotypical people don’t do this? it’s so very mentally and physically draining for me, but because it doesn’t affect anyone around me it feels as though i should be doing fine. but i’m really not. it’s so stressful, i really don’t know what to do next. am i going to live like this for the rest of my life?