I'm in the same situation, I've barely done any revision during the Easter holidays. I'm just trying to tell myself how disappointed I will feel when I open the letter on results day and haven't met my expectations.
I'm just thinking that I wont be able to enjoy the long summer if all I keep thinking about is how bad I've done in exams.
Try to keep your phone as far away, it's my biggest distraction honestly really frustrating how attached I am to my phone sometimes.