Some of my best advice would be to remember why you are studying and focusing on why that is important to you. This always helps keep me motivated to study when I can. It is important to have a goal, even if it seems large or difficult to reach.
For example, a long term goal is always great motivation; for me, I personally have a career goal that motivates me to work as hard as I can so that getting that job and moving into that work sector will be slightly easier. This goal will allow you to have a reason to focus and revise, even when you really don't feel like studying (but don't forget to take some breaks, they are a necessity for your mental health).
One other really important tip from me is that if something is becoming overwhelming, step back from it and try to think logically.
For example I always try to split up each task into smaller more manageable tasks, this allows you to not only calm yourself down and manage it better, but it will also allow you to plan the order in which you do your revision.
For example, I broke down my geography revision into the main things that I needed to cover for upcoming exams, and spread out the revision across multiple days, as I knew how much needed to be done, and what would be a suitable time frame for that amount of work.
Follow Tammy's studygram on Instagram @studying._.4
Follow MyMindsMap on Instagram @mymindsmap for more