I've actually experienced this. I was diagnosed bipolar after a rather severe psychotic break. Up to that point I had defined my life as being a terrible person striving to become better.

Medication very quickly showed me I was not a terrible person, but that I was suffering severely from mania and even more dangerous paranoia.

As I stabilized, everything that defined me was stripped away, leaving an empty husk. I very quickly realized as traumatic at this was, it was a start to healing and an enormous opportunity. During that process, I got to choose who I would become.

Now, a few years later, I'm happy with who I am and plan to keep improving. Medication has allowed me to sit down and focus on creative things instead of being overwhelmed and scared all the time.