Diary

Today I received another internship communication, um, it'sopportunity. It's also a company I really like.

-I think another word than 'communication' would be better. There are a few options, depending on what you mean - "I received another internship interview," "I received another email about an internship." -You have used 'um' correctly. That would be very normal to say when speaking, or even maybe in a text. It is a little strange in a more formal written thing.

At the same time, I also went to a big clearance sale around here today., the The clothes were all super cheap, so I bought three piecesitems.

-'At the same time' suggests either that the two sentences are very related or they happened at literally the same time. You could say 'around the same time,' or 'that same day.' -Pieces is fine, but it isn't usually used for clothes. That would be three pieces of furniture or paintings.

Today I received another message about an internship communication, um, it's also a company I really like.

unless you mean you were offered an internship, in which case you would say "I received another internship offer"

I got a bit hooked, and I think I want to go again tomorrow.

No change suggested

"I'm hooked" or simply "I loved it" would sound more natural