Dear OP as you haven't mentioned suffering from any illnesses like Fibromyalgia etc then I think that you may be suffering from depression. Not wanting to get dressed, not being bothered about leaving your home at all, in fact really not being bothered by much at all, can all be classic signs of depression. Do you go out shopping? Do you take the children to a park? Have you any children who go to a nursery or of are school age? If you do go outside for any reason, do you still wear your pjs or leisurewear then?
In non Covid times, before many GP's decided that actually they don't need to see their patients face to face, or even refer their patients to people like cousellors themselves, then my first reaction would have been to advise you to see your GP as soon as possible. Unfortunately I can't see any other way around it though - unless you are one of the new mums who is fortunate enough to have a good health visitor? If you do, please confide in her, she might be able to help you get to see your GP face to face? If those options are not possible then you may need to be prepared to have a telephone appointment with your GP, but your GP does need to know how you are feeling and coping, because how you are feeling right now does not seem to be very good for you.
Do you have any other support apart from your partner, maybe close family near by, or good friends (preferably ones who are parents themselves)? The phenomenon of parenthood, and sorry dads - some of you are brilliant - but the phenomenon of motherhood, especially if it is for the first time, makes a massive shift in most of our psyches. We suddenly have a tiny human being almost totally reliant on us, but in the background, unless we are either very lucky in our support from a partner or family, or unless we are wealthy enough to buy in extra help with running the house and/or helping with the baby, we also have to manage our homes, feed the inmates, and keep that little bundle of terrifying treasure healthy and happy. I am sure there must be some mums who can pretty much take all that in their stride, and still manage as an almost fully functioning human being as well. I fell far short of that "ideal"(?), especially with my first baby (baby numbers 2 and 3 somehow became easier to handle, something to do with experience I suppose).
So if you do turn out to be depressed, for whatever reason - I feel like you may not be getting enough physical and emotional support from your partner - the sooner you can get some help the better.
Even if you are not depressed, but maybe a bit overwhelmed (and very few of us have had any experience of new motherhood during a world wide pandemic, the mental stress of that on top of a new baby would be enough to overwhelm anyone) then that can easily lead us to only concentrating on the essential things that need to be done everyday! So please try to not judge yourself, and if anyone close to you, but particularly your partner, is judging you, then they need to get some empathy from somewhere, and fast.
The main problem with your lifestyle at the moment, whether it is contributed to with depression or not, is that it is not healthy for you in the long run. If it is for a limited time, eg you return to work in the New Year, then it can probably be managed until then, but if not, then I still think that you could do with some sort of counselling and professional advice.
I am sending you a big hug OP, because your life at the moment sounds very confusing for you, and not very enjoyable, but if you don't want the hug, either return it or throw it in the bin! The important thing is to take care of yourself, go easy on yourself, don't let anyone guilt trip you, and congratulate yourself that despite everything that is going on in the world today, you are bringing up a precious baby with your love and energy focused on him or her.