Post diagnosis' low mood.

Hi all,

I was officially diagnosed 2 days ago. Even though i was pretty certain that i was autistic, the diagnosis has really affected me. Initially i was pleased with the validation finally as a 38 year old female i was fed up with having to justify to people why i am autistic as not stereotypical. Anyway once that wore off i have felt completely flat and shut down. Did anyone else experience this? I did not expect it to affect me at all as i thought i had accepted the fact that i am autistic. 
I have of coursed looked this up and read about late diagnosis grief? is that actually a thing?