When I was in this position I was also a bit worried. However, realistically it shouldn't make too much of a difference as long as you don't leave things to the last minute. If having a day between exams to revise would be of significant benefit, you may have already left your revision too late! If you can strive to be prepared well in advance of your exams beginning, the only thing you'll need to worry about is making sure you get a good nights sleep prior to the day and then try eat a good lunch in between the exams! It isn't as scary as it seems I can assure you, I'm sure you'll do great and good luck!