I have been through the same situation. Next time, wear some ear plugs. The sound appeared to get loud because your brain decided it could not filter it out anymore. It got overwhelmed and focused on the sound which is what made it sound louder.

I have learned that as soon as I notice that 'focus in' hearing effect, I know I need to find the exit.

Dollar stores can be very tough because they are extremely visually over-whelming. Add some sound and it is a perfect storm.

Rather than going backwards, I think you just had one of those perfect storms. As time goes on, hopefully, you will learn how to recognize these triggers. Use your observations to build your tool chest of getting out skills. Some days, you will be more tolerant of stimuli, other days, you will have no tolerance.

I can tell by how easy it is for me to 'stop to think' If I can get focused easily, I will usually do better out in stores and such. If I need to work harder to focus, I know to be careful going into stores. We call these good days, driving days and the bad days, no driving days. In time, you will be able to recognize these signs.