I dont, and never have, fitted in here

Ive never really fitted in here.  Im not clever enough. Im an average kind of person, of average intelligence, surrounded by people who are, and always will be, streets ahead of me. They were born of intelligent parents, and went to public schools where they became more intelligent.  The only reason im here is cos I was bullied at state school and compensated by working hard. Always got low A grades. Always LOW A. I never really excelled. Even at university, I mastered getting a low 2.1. I scraped a PhD. But I never really understood what I was doing. I dont have the spark that clever people have.  You see that spark in people in all walks of life, and in all professions.  I am, and always will be, dull.  I have no real creativity or genius. But after going to the top uni in the country, and getting a top degree (a PhD for fucks sake) how can I ever get a normal/average job? Ill always feel inadequate, inferior, out of it. Stupid. And after years of drinking, I feel like my brain is rotting. I can rarely think straight or with any clarity any more.  I dont think I can ever fit in anywhere now.