hello! i’m a 27y f, diagnosed Bipolar Type 1 a few months ago. I experienced what I now know was mania, and that led to psychosis which is what landed me in the hospital. This happened shortly after my dad passed away from Stage 4 lung cancer, 8 months after his diagnosis. 
Now I’m on lithium, which hasn’t given me many side effects aside from thirst, and I can’t sleep in like I used to. (I work evening shift.)
But this was my first time experiencing mania, and I’ve had depression in the past but it was situational. 
I guess I just can’t believe because of this one episode, now I have to be on medication for the rest of my life. My therapist agrees that it could have been a response to losing my dad, but I’m also nervous to go off the lithium because i’ve heard it loses its effectiveness when you go off and on, and also I am finally starting to feel less depressed after my doctor upped my dosage.
Has anyone had similar doubts about their diagnosis?