I'm thinking of not telling my bf of a year about my mental illness
Why don't you want him to know about your mental illness?
I'm just still scared that he will leave me when he finds about it
I understand how you feel, but I think it would be good to talk to your boyfriend about your mental health issues. If he cares about you then he'll be supportive, and if he isn't then he probably isn't right for you anyway.
Okay, I think I love him.
I'm glad and I'm sure he loves you too! And I'm sure he'll be fine that you have mental health issues.