Our son's SPD didn't become an issue until he went to preschool and then it became more of an issue at school... in different environments with more demands (ie stress) on him he coped less well. The stress thing becomes a spiralling cycle then too, more stress less coping, more stress etc etc. The OT can help you start to work out the triggers and issues for your daughter - every child with SPD is just so individual, it has to be done on that individual level and it can take time to sort through it. My son's underlying issue was his auditory processing and it took a while to come to that realisation, now we look back on it we've all thought "of course, it's so obvious" but it's not always.

As Sarah says, you are a mother. You worry. You're fulfilling your performance criteria indicators. Give yourself a payrise! (Don't we wish....)