Being a research student is really tough. I mean tough! The most difficult part is keeping up the self discipline, day after day, week after week. As a research student, you make your own schedule, you even make your own syllabus pretty much. I handle the syllabus part just fine, but I struggle with maintaining a disciplined schedule. It takes a while to get into a stable rhythm where you work according to plan and remain focussed on the task at hand, for however long it takes.