Need advice/ difficulty to refer myself for assessment

Good afternoon all, 

I am 39 and since late teens always known that I do not think or behave like other people. My mum had recently been diagnosed with autism at 57 even though for years she has battled with mental conditions such as bipolar she was shocked to learn that she has had autism but in the positive of this she now knows why she has been struggling so much with herself/life.

now me, I have very similar traits to my mum and finding it extremely difficult to talk to anyone about it. Since her diagnosis it is the first time my mum has shared how she been feeling/behaving and acting and I can completely relate to it! No bright lights, patterns of repetitive behaviour, have to have a clock to keep eye on, no social skills (cannot sustain friendships at all)I have to have a routine, cannot be disruptive from what I am doing, people if out of sight they are out of mind including family. People think I’m stuck up/rude as I do not talk, see them or give them eye contact and more!

How did anyone approach it with a GP? I do not feel comfortable just ringing and telling them direct. It’s getting me down so much as I have always been strong and not let this get to me but cannot do this anymore it’s burning me out! This is the fist ever in my life I have reached out to anyone. 

thank you