Don't beat yourself up too hard, remember that by just writing on and reading this forum is already a good start to becoming free of PMO. Get educated and stay focused.
A helpful tip, that has helped me somewhat, is using a "spreadsheet". So instead of a day-counter you can just mark in your calendar the days when you PMO. There's no need to count on what day you're on. That way you can see progress and every time you PMO it doesn't feel like your back at the beginning (ie. back to day 1), because you obviously aren't. Every day that you combat this addiction is a step forward.