Hi and welcome. I am wondering why you were so quick to throw out the suggestion of autism spectrum disorder? Many children miss an autistic spectrum diagnosis when one is actually valid. This is especially true for young girls who present differently than boys on the spectrum (can't tell from your post if your are male or female). Reading your post I did get a sense of many autistic traits in you. That is not to say you ARE on the spectrum... we all have autistic traits to one degree or another. Traits do not a disorder make!
But I do wonder if it revisiting ASD as a possibility might help you find some answers.