would my case be worth doing

my dr told me sign up on my ssi cause of my mental illnesses i use to get it when i was younger but my mom had it stopped my dr has been seeing me since i was 13 years old and i am 27 now i have a learning disability and few other things i recently got denied because they said i was able to work they said i was a 8th grade level but i hae scores from me ged class that shows im just a 3rd grade level they really aint test me like they should have asked me a couple questions and said i was done for it to be a mental exam it wasnt what it suppose to be my 5 year old could do it and shes in kindegarten they just asked me kentuckys capital and say a couple numbers backwards but like i said my dr told me to do this he believes i deserve it and told me if i got deied to get a lawyer