My partner believes i am bipolar/depression. how to i get myself to seek treatment when i'm having depressed symptoms? (no motivation, self-loathing)

Ask for help: I would begin with seeing your primary care physician who can rule out medical problems and identify an appropriate referral if one is indicated.

You are seeking!: Asking this question is a big step in the right direction. It might seem insignificant, as you say, depressed symptoms can really put you in a bind when it comes to getting help. If you don't have the energy or motivation to find a therapist, ask your partner to help. It might be easier to get help than you think. Good luck.