The first few weeks is so hard I found by around 4-5 weeks I had my routine down, but occasionally got thrown a curve ball of an awful nights sleep and would spend the day in my pjs.
My lo is now 19 weeks, so have very recently had a baby.
As pp have said your dh really needs to step up, also do you gave any other help? The first couple of weeks my Mum or mil made us dinner most days.
I found porridge pots the best thing for breakfast, it's not too difficult to boil the kettle and that's all you have to do. I've moved on to making bircher muesli now. Also Bol veg pots/salad jars for lunch or making a pitta/sandwich the day before.
I second a snack bag/box in the room you spend the majority of your time feeding. I loved Graze superfood bites they're really tasty and fairly filling, lots of things you like and can eat one handed. As pp have said I also had a big water bottle as I found I was getting awful headaches from forgetting to drink, I kept this with me and found it really helped.
If you can afford it don't feel bad to order in dinner.
Hope you can start to get more help, it's a hard few weeks but you will find your new normal soon.