If you’ve been training hard for any length of time, you would expect to have seen progress, which is motivating and encourages you to keep going.
The problems can start when you no longer see the results you expect, even after increasing the reps/volume. This could be one of the signs of reaching a plateau, but it could be you’re overtraining. Are you getting injured? Picking up every bug? Feeling irritated, de-motivated? These could all be signs you need a break.
Having a rest week won’t scupper your long term results any more than it will take away from all the hard work you put in to get to this point. Enjoy the break and use it to plan a comeback that won’t cause you to overtrain.
Seek professional advice if you’re unsure what to do, someone else looking at your training plan might help you make changes that will see you get better results.