English exam

Finally, after studying my English course, I didn't pass the intermediate exam, which was at the fifth level.
I need to study more and practise a lot.
Thankfuly, I have several months ahead of me to study for my next exam.

English exam

Finally, after all the course, I didn't pass the exam of 5th level, the intermediate level.
I need to estudy more and practise a lot.
I have several months ahead to get enough level before the next exam come

One Possible Correction- After completing the entire level 5 intermediate course, I took the exam and did not pass.

I need to study more and practice a lot. (I believe if you're using UK English "practise" is fine.)

I have several months to prepare before the next exam date arrives.

Hope that helps!