Identify the things that trigger your anxiety, or stop you peeing. Put each in order of perceived difficulty e.g.
door: locked, unlocked, cracked open, ajar, fully open
type of cubicle: solid walls and doors down to floor, gaps at floor level, gaps round door
number of cubicles: lots, two, one
busyness: quiet, moderate, busy
neighbour: adjacent cubicle unused, in use.
Start with the easiest setup for you and write it down. e.g. locked door, solid walls, lots of cubicles, quiet toilet, adjacent cubicles unused.
Then alter one of the components (say door) and change it to unlocked and write that scenario down.
then alter that one again to say cracked open; or leave it unlocked and change one of the others.
And so on
Find a suitable location, fluid load, go into it and do a 3 second pee (in order to keep a reserve).
If that was a bit uncomfortable, you need to repeat it until it is comfortable; when comfortable, move up a step in your list above. You can either leave and return in say 5 mins, or stay in the cubicle and change the item (in this case unlock the door).
I hope you see that it is an incremental approach; each step introduces the minimum possible amount of anxiety. You now see that it is not a quick process, so have no expectations. Just accept progress will happen.
Hope that helps
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