It sounds like you handled that maturely, and about as well as you could. It's not like you can just choose to be less sensitive.

I’m going to suggest something probably kind of dumb, have you tried deep breathing exercises? I’ve found very little able to calm me down as effectively as deep breathing. More is better, but even just a few cycles makes me feel noticeably calmer.

Mental health is just as important as physical health, but is often ignored because it's harder to see.

You wouldn't try to keep walking on a dislocated leg even if it's just been relocated. You'd give it time to heal before putting your full weight on it.
Trying to push through sensory overload is just like trying to walk on an injured leg. It's only going to make the symptoms worse until you stop and take care of it.

Any reasonable manager would give an employee the day off to recover from a physical injury, so why would mental health be any less valid? You don't need to give the manager a reason to go home other than you weren't fit to work and needed the time off.

The planning you mentioned can help, as can learning to identify when you start to feel overwhelmed and acting early. Early action often means less drastic action.

The people who talk about "gritting their teeth" and "always pushing through" have never reached their limits and don't understand that it's terrible advice. When you reach your limit, something has to change.

Given the circumstances you described, I think the decision to remove yourself from the stressful environment was the best decision you could have made.

I'm proud of you; both for how you handled the situation, and for how you're learning from it.

I think as others here have said, by the time you made it to the bathroom, leaving for the day was absolutely the right decision. In terms of trying to prevent getting there, I have a few suggestions:

• Telling your manager you need to take your break early, and take a bit more time than usual (even if that extra time needs to be unpaid). I don't know where you are in the world, but if it's safe to do so, tell them you'll need to head home otherwise.
• Changing up your sensory environment to regulate. What I mean by that is find ways to assuage your five senses.
• Sometimes that looks like completely removing a senses input, closing your eyes, or keeping some earmuffs in your bag.
• Sometimes it's doing something that is sensorily pleasing. Something soft that's comfortable to touch, or a small snack that you like the taste and texture of.
• Smells can also help. I don't want to sound like an essential oils saleslady, because most of it is woo-woo fluffery, but sniffing from a bottle of lavender oil can be really calming for me. It can be like a sensory reset.
• Most importantly is finding the things that work For You, and that can take some time and experimentation. I like putting on music with a heavy beat that's not too fast, it helps me regulate my breathing.

I hate those days where I keep bumping into things, knocking things over, or hurting myself. It’s like some part of my unconscious brain is somewhere else and even if I don’t have a meltdown I’m better off finding a safe place. Mindfulness or deep breathing can help me with the anger, but the other issues continue until I’ve had a good night’s sleep.

For me, it’s also often a sign that I’m fighting a virus. Usually I’ll get sick within a day or two of experiencing this.