Sometimes iI need to reboot myself.

"I" is always capitalized

On days like these i/this, I can't work or learning somethingstudy.

Typically, we would say "days like this," which is referring specifically to THIS day in question. But you can also say "on days like these," it just means the same thing but in a plural sense.

Devoting time to learning = studying

The best cure for me is to gohike on the mountain or lie on the beach with sunscreen on my porcelain skin.

We tend to use more descriptive verbs other than the default "go" when it involves something as massive as a mountain, such as "hike," "trek," or "climb" if it is particularly steep.

I think most people need a timeout in life sometimes.

It's good to add "sometimes," because otherwise it can be interpreted that everyone in the world needs to take a break RIGHT NOW.

Additional synonyms for sometimes: now and then, here and there, from time-to-time.

If I stay at home, iI apply a face mask and read Ssci-Ffi books, like Azimov's "I, Robot," or watch movies.

No need to capitalize "sci-fi."
Titles of books, movies, shows, etc. should either be put in quotations or italicized.

My favorite is GATTACA.movie is "Gattaca."

Since you were talking about both books and movies, it's good to specify this is a movie. No need to capitalize every letter.

TheI am a weird case with, the girl in a face mask, but that's life, and we're all a little crazy.

I assume you are talking about yourself :)

How do you get yourtake a break?

Sometimes iI need to reboot myself.

On days like these iI can't work or learning some anything.

The best cure for me is to go ton the mountain or lie on the beach with sunscreen on my porcelain skin.

If I stay at home, iI apply a facemask and read Sci-Fi books, like Azimov's "I, Robot," or watch movies.

The weird case withof the girl in a facemask, but that's life and we're all a little crazy.