Hi Luga and a very belated welcome to the forums.
There seem to be a few posts slipping through and missed lately and I wanted to make sure you knew it isn't a reflection of anything you've written. I hope you can return and keep joining in.
I found myself admiring the self awareness in your post. It is such a positive thing that you're aware of your own needs and limitations and are focusing on what is within your control. One comment that comes up on these forums often is the saying in an aeroplane emergency... "secure your own mask before helping others". Although you clearly care for your partner and want to help right now what you're focusing on sounds like a good plan to me.
You mentioned you live separately and aren't sure whether to contact her. My thought on this was to wonder what is 'normal' for you both as a couple (in terms of how often you contact eachother and how when you are feeling well and times you've been down before)? Can you think of approaches that have worked previously or is the isolation something new?
One thing I find myself returning to often is the 'love languages' theory. It might sound a bit silly but it does help my husband and I to remember we express and feel love very differently.
When I'm depressed I can't always see his affection because he shows it differently to me and I isolate myself more feeling rejected thanks to the black dog in my head telling me I'm unloved. For example he shows love with acts of service but when I'm low I see him keeping busy doing 'things' when all I want is for him to give me a hug or just sit close.
Do you think seeing as the approaches you've tried so far haven't worked that this might be a place to start to find ideas of different ways to show her you value her?
It's ok if this isn't something you find helpful. I can relate to your partner's behaviour (hibernating is such a good description!) and figured I'd share what we've found helpful.
I hope you can find an approach that works for you both.