How long do you have left til your first exam? Maybe your revision timetable isn't up to scratch. Set what you're going to revise each day (or each hour, if you want to be that specific). Make sure you set equal times of revision for all your exams (or remove some days for the less important/easy ones and substitute time in for those that are the far more important/hard ones). Of course always make sure you revise a subject the day (or two days) before its exam. Also predict how long you're going to remember the information you've taken in. There's no point revising for a subject 30 days prior to the exam if you're just going to forget it in that time. Structure it around how well your memory can cope with information you're going to take in.
I used to count revision on days with school as '0.5 points' and days without school as '1 point' - just to make sure I kept equal time amounts of revision for all exams.
It sounds simple and lame, but I found putting my exams in a timetable kind of helped me get motivated, and didn't create the chaotic thoughts of "Ohh....what should I revise next?!". I used to revise all the information twice and then go straight to past papers, maybe making notes might help (they do for maths and physics equations).