In what way do you feel like a piece of shit
If you feel like a piece of shit as in a bad person then usually playing a videogame I like for a bit and then having something to eat and going outside if it isn't too hot/cold works for me, but it'd be even better to eat said thing outside if you're already able to go outside, if you feel like a piece of shit as in you feel sick then usually drinking some water and getting some fresh air and then taking a nap or just laying down for a while helps a lot