How to deal with slow progress & fear of weight gainWatch
In other words, first celebrate what you have done so far, and I'll add very well done for your achievements! Second, consider what you have left to do in terms of weight loss; it's now a much smaller number than when you first started.
You didn't go "what can I do for the end of A-levels? I know, I'll lose weight." You decided to lose weight, and happened to choose a date. However, you are doing exactly what you set out to do, so forget the when, it's arbitrary. Focus on the what and why; weight loss and health benefits. Best of luck!