T.N.
Hi M., many children have just one sense that is super sensitive. Instead of removing her or protecting her from the offending situation, I might suggest you teach her coping skills, as such situations will very often be outside your control throughout her entire childhood. If you haven't already, google SPD and I'll bet you'll come up with a Zillion ideas to coach her, to give her the skills she needs to work through those moments.
Another thing, is kindergarten, her age is a pretty common time for behavioral changes.
Personally, I have some sensory issues myself. I despise going to the movies, for example, it's TOO loud, TOO dark, feels like an attack to me, and the dark no window closed door feeling creates a feeling like I'm trapped. So, I just wait til I can buy it on cable, tehehe. I also cannot stand a loud TV, a very small well lit bathroom, etc. On the other hand, I REALLY enjoy rock concerts, play my ipod really loud in the kitchen while I'm cooking...
I'd have to say all three of my kids after settling in at 4 in preschool, had a little phase in kindergarten, but that's all it was, a phase, a time of adjustment.
As far as the bus is concerned, my kids have never ridden a school bus. I drop them off and pick them up every day. It's not that I have some strong aversion to school busses, or want to shelter my kids from it, but I ENJOY bringing them to school, especially picking them up. For the taxi years where every night it seemed I have three different kids in three different counties at three different must see sporting events, the car ride home from school became our dinner table. I think if I'd had to go to work or some other reason why I COULDN'T drop off and pick up everyday, they'd've been just fine. If they'd had school bus issues, I would shown them hope to cope with it rather than yanking them off the bus.
Anyway, if you see a NUMBER of sensory/behavioral issues, discuss it with her ped, perhaps it's time for an eval by a developmental ped.
Good Luck!
:)