Then just do English. If you are too tired, you just must set priorities. What is the most important? What can wait for later? How much time do I have? And then make a plan. Also, it mostly is more beneficial to know one thing good, then a lot of things half. So, better fluent in English, and bad in Korean, than know a bit English and a bit of Korean, but not enough to get you a job.

but still need to learn English

My advice, focus on fewer languages. Just do German f.e.