i would say some of the psychs diagnosis is correct.

you are clearly an articulate and thoughtful girl. thus i do not think he is right about your IQ. it is not an accurate measure of your abilities. most 18 year olds i know with IQs of 100 cannot string together a sentence and are not reading books for fun.

but i cannot stop asking myself why you care so much. why is your identity so wrapped up in what some professional using clearly inadequate instruments thinks of your intellect? or why you care so much about the opinion of strangers on the internet? It leads me to think either 1) you are a troll just messing with us. or 2) you are seeking something you are not finding in your current environment. and the dissonence you feel is causing you to try to grasp at things to try to force them together to make sense.
perhaps you are one of the different ones, not fitting where you were planted and not yet knowing how to find a place to fit.

I would encourage you to continue to seek something more. it may lead you on an exciting journey. you may never find where you belong. but the journey just might be extraodinery.
you say you are 18. are you done with high school? will you be able to go to college. are you feeling like you want to go on to more education but cant go on to college because of the expense. do your parents not value education? or think you arent suitable for college?
you are not your parents image for you. you are not the limits of some experts assessments. you are whatever you can grow to be. and you have a lifetime to do it in.
keep reading, keep dreaming. but in the meantime figure out how to get to the next place you want to be..........