I felt the same fear of becoming someone else. When I first took my meds the person I found was the version of me that I missed. The version that's happy because they accomplished something today. The version that isn't feeling like a lazy loser because they weren't able to do tasks that should have been easy.
You won't lose yourself.
The trick is that in order to "still want to fuck" you, she has to have wanted to fuck you in the first place!