You don't always have to be a new york runway model 24/7, Let go sometimes. Going to the shop doesn't require a full face of make-up.
Here are ideas of just being comfortable.

1. Oversized Hoodies

Oversized hoodies are literally the best thing that has ever existed. Feeling insecure, Here wear an oversized hoodie, wanna feel comfortable at the movies, O V E R S I Z E D hoodie. You can just flap around in them because the sleeves are huge and why not just feel like a fish.

bowling, girls, and sweater image purpose tour and justin bieber image

2 Leggings/Joggers

Honestly feeling like you are in a warm blanket in the middle of winter with your oversized hoodie and joggers maybe even a nice hot cup of coffee.
Slipping into some leggings just makes me want to lay down and watch a movie. there is nothing wrong with being comfortable :)

fashion, grey, and outfit image fashion, style, and outfit image

3. SOCKS

Go crazy with the socks add some colour, or just some whack socks to just give the comfort some colour

adidas, banana, and black image Image by Femkevanbrabant

4. Shoes

Slides, Sneakers, Slippers etc etc etc there is literally so many options here honestly whatever floats your boat chuck em on. Whatever feels comfortable to you. Don't let some fashion nazi sink your boat.

Image by Femkevanbrabant yellow+pink+white, fashion+beauty+girl, and indie+alternative+grunge image

Well that's all folks hopefully this gave you something
:)