It all depends on if you are one your own or have a family but I would put yourself first.
Exercise, try something you can do at home - I’m using Lucy Wyndham-Read at the moment as I haven’t been able to exercise for a month. I’ve just done a 12 minute low impact/high intensity one, she also does 7 minute ones, try to do one a day, it makes it easier to get into a habit and then you might want to do longer ones later on. Also walk outside if you can each day for 10 minutes for the fresh air.
Go to Superdrug if you can. Their skin care is excellent, the hot cloth one is easy to use and works, they also do good toners and face cream. If you need make up the vegan one they stock is incredible value for money when it comes to brows, eye liner and mascara. Go to the shower gels and find a scent you love - it doesn’t have to be expensive - so that it feels that each day begins with a treat for you, try the same with hand soap. All of this confirms that you matter and deserve to be looked after by yourself.
Next meal plan. There is a good thread going atm on what a seven day menu looks like, if you have a family this will help with ideas, if you are on your own it will help you to add fruit and veg to every meal, add porridge for breakfast, soup and a roll for lunch and you’re good. Jack Monroe also has some good recipes on her web site. Treat yourself to some ground coffee, a small cafetière and a thermal mug and have a good coffee once a day, it will keep hot if you are out, at work or at home, you can also use it for water, keep a glass you really like for your water at home, you could look in charity shops to find a special one and use it at least 4 times a day - unless it’s a shot glass.
I’ve just helped a friend with a small flat deal with clutter without - yet- throwing anything out. Of you are on your own or have a family, do the bathroom first. Clear the floor, put anything on the window sill/ bath, in a plastic box, that makes cleaning easier and will make showering a better experience, the aim is to make it a pleasant place to be. Do the same with the kitchen, make sure surfaces are as clear as possible, group things together so it looks planned not a mess if they are out, clean. If you live on your own do your bedroom next. Same process, make space on the floor, I use bags for shoes, out of season clothes, these can be put under the bed, around the sides, if you have a family do the living area in the same way. Keep a bin bag handy for any rubbish and chuck it out at once, anything you are uncertain about put in a bag or cupboard.; you can deal with it later when your living space isn’t cluttered.
If you have a journal write it up each night, try to achieve 3 things a day, one for you- exercise, shower, one for the house - de clutter and clean one shelf and one for the future such as make a healthy meal, even if it is a microwaved banana with yogurt and a square of dark chocolate!
Good luck 