Being Single-minded

I would say it is an art to be single-minded whenever you need to complete a task either about your work or about your studies. Over time, many colleagues and friends of mine said to me, "You have to be single-minded; otherwise, you can't finish your studies." All of them are, of course, out of their good intention when they gave me this friendly reminder. I have tried very best to concentrate on my studies whenever I'm free. However, studying a higher degree as a part-time student, I find it very difficult to be single-minded. As a teaching staff in my institution, I have to teach a lot of courses in a year. On top of it, I need to take up some administrative work. All these commitments are mandatory unless I quit. So there is so much ahead of me to accomplish. I haven't counted my family and parents. I feel a bit guilty that I always have no time to talk to them or even see them especially my mom and dad. It is easy said than done to be single-minded! Things won't happen sequentially.