first italki notebook. 

I'm studying chemistry right now. This is program of university class (don't understand what a program of university class is-are you taking a chemstry class or are you majoring in chemistry?)!!so hard, but very interesting. (<-- this is grammatically incorrect but something I would write. If you want to be grammatically correct, then you could write-- "It's really hard, but also very interesting."
I'm bit a tired so I'm taking a little break now.
I abusolutely "really" is a better word want to improve my English skills because someday, I want to study abroad someday....

I just changed stylistic of your writings, hope it helped.

*

First italki notebook.

Curently I'm studying chemistry. This is one of the modules of my major degree at university.** It is really hard, but yet so interesting!
I'm a bit tired, thus took a little break now.
I am determined(or am absolutely want)to improve my English skills, because I will pursue my education abroad. 

*

Red - grammatical errors.
Blue - stylistical improvements (not necessarary wrong, just author's sugest his way of interpretation)
** - I changed the whole sentence, as initial sentence was quite confusing. However, later, in the comment section, you explained that you are majoring 'Pharmacology', which leads that 'Chemistry' is one of the subjects you need to study. In western universities they called modules. Although I am only referring to UK universities system.

Comments: 

You have few mistakes, but overall, you wrote well!
Well done! Good luck with preparations, never give up, you can do it!