Oh, Beth, don't be too hard on yourself, it happens even to people without MS. I'm an advocate of napping, it gives the system a chance to regroup. This may sound odd, but have you tried using earplugs? The swimming kind don't blot out all the noise, just some of it and that can make a big difference for me. Even dry cotton balls might do the trick.
Have you talked to your neuro about these sensations? There may be basic coping skills that you can silently work through to keep the madness in check.
Last fall, I discovered that I can't go to movie theaters anymore, it's too overwhelming for me. But, if it is something that matters to my mates, I find that earplugs and shutting my eyes frequently will often help me curb that panic feeling.
Feel better, sweetie, take care of yourself.