Hi Arana - this thing with your DH is a bit of a puzzle. Have these ambivalent feelings towards him come since the depression started, or did you feel like this about him when you were well. Ah think you have answered that because you say the "mental health issues aside we have a good relationship" - SO it is it seems related to your mental health difficulties at the moment. The thing is I think depression manifests itself in different ways with people, and of course we only understand the way it affects us
You really should not be making decisions (leaving him) while you are so unstable because of the depression, and you have the insight to know that when you are well again you would be distraught if you had made him leave.
Do you have any understanding at all about the reasons behind the way you feel about your DH at present - is there something you need from him (support, empathy) that you are not getting. Are you envious because he is ok and you're not, (oh sorry I see you are saying you don't know where the feelings come from) but I am just casting the net as wide as I can to see if anything rings bells for you. I think you said in one post that everything he does irritates you, and depression can make you very irritable and I hated that, more than when I was crying and vulnerable, because it elicited a better response frommy DP I suppose.
Is there any chance you can sit and talk to him about this dilemma, and help him to realise that it is hot him that you are irritated/angry/frustrated with (whatever fits) but it is the way you are feeling, and thus far you haven't been able to understand these emotions, and so have chosen to be distant rather than horrid. OR if you can't talk to him, can you write down what you are feeling and how muddled you feel and let him read it.
The real solution though is to get your anxiety and depression sorted and get different meds to see if they will help. I think you are just in a state of thinking "the meds don't work" so what's the point, but it is always worth talking to the GP or ask for a referral to a psychiatrist, who may be able to offer more help than a GP. I had a friend who tried so many different ADs and nothing worked and she was pretty awful for well over a year, and then she saw a psychiatrst who added lithium to her ADs and that worked and she gradually got better and is fine now.
Take care of yourself - you are going through a horrid time at the moment, but it will pass, but you need to get back to the GP and if necessary ask for a referral to a psychiatrist, as they obviously have an expertise in diagnosing and treating dep/anx that many GPs just don't have, and would not be expected to have. It's like any pyhsical illness - you sometimes need to be referred to a specialist. First thing is to get back to the GP and take it from there.