These are words from someone who is.
Shower. Not a bath, a shower. Use water as hot or cold as you like. You don't even need to wash. Just get under the water and let it run over you for a while. Sit on the floor if that's what you prefer.
Moisturise everything. Use whatever lotion you like. Unscented. Bargain basement lotion. Top of the range that makes you smell like a field of wildflowers and honeysuckle. Use whatever you want and use it over your entire dermis.
Put on clean, comfortable clothes.
Put on your favourite underwear. Cute black silky ones. Those boxers you bought last Christmas with a reindeer on them. Who cares? Put them on.
Drink cold water. Use ice. If you prefer add some mint or lemon for an extra boost.
Clean something. Doesn't have to be anything big. Organise one drawer of a desk. Wash five dirty dishes. Do a load of laundry. Scrub the bathroom sink.
Blast music. Listen to something upbeat and dancey and loud, something that's got lots of energy. Sing to it, dance to it, even if you're pants at both.
Make food. Don't just grab a granola bar to munch. Take the time and make food. Even if it's pasta. Add something special to it, like some soft boiled eggs, or veggies, a dash of sauce and a bit of your favourite . . . .
Prepare food, it tastes far better and you'll feel like you accomplished something.
Create something. Write a short story or a poem, fold origami, crochet, knit, sculpt something out of clay, start a jigsaw. Even if you don't think you're good at it. Create.
Go outside. Take a walk. Sit in the grass. Look at the clouds. Smell flowers. Jump in a puddle, Put your hands in the dirt and feel the soil against your skin.
Call someone. Call a loved one, a friend, a family member, or a chat service if you have no-one else to call. Tell them how you feel. Have a conversation and listen to someone's voice. If you can't bring yourself to call, text or email or whatever, just have some social interaction with another person. Even if you don't say much, listen to them. It helps.
Cuddle your pets, if you have them/can cuddle them. Take pictures of them. Talk to them. Tell them how you feel about your favourite movie/person/walk/place — anything. They'll listen — even cats.
