I think to start changing this mindset would take some conscious choice - reminding yourself that you don’t have to be perfect to be found worthy of love by another person, learning to accept and love yourself for who you are.
Admittedly I understand very little about bipolar, so I hope these aren’t totally inappropriate suggestions (I also admit I’m not handling the knowledge I don’t love myself very well right now, and I also don’t have a super strong attachment to my own T but it could happen. I don’t think I’d handle that very well, either, so maybe I’m being a little hypocritical here lol).
Nobody deserves to feel ashamed because they like someone else, though.