Aw, do you know what - I don't know anyone who hasn't felt like this one time or another, and I actually don't believe anyone who says they've never shouted at their children.
What I try and do to keep on top of stuff is to tidy up as I go - so, at breakfast, as soon as the cereal has been used, it gets put away. As soon as the dishes have been used, they get cleared. As soon as the milk is finished with, it goes back in the fridge etc. And every time I go upstairs I take something with me that belongs upstairs. Every time I come down, I bring something down etc. You get the picture. If I let things get out of hand, it piles up, and then the thought of doing it is so daunting that it doesn't get done. So, I try and do the daily things, plus one extra chore each day, maybe the hoovering one day, the windows the next etc.
But nobody's perfect, and its ok to have a bit of mess. Most of my dc are older now, so really there's not much excuse for me, but my house is still, and always will be, a long way from perfect. Just getting through a day is draining sometimes, and if you have anaemia, you're going to find it even more challenging. Be kind to yourself.
As for Christmas, don't worry. It's still only November! . Do it on-line - Amazon will even giftwrap for you if you like.