Sensory disorder, stress, and reading

(Florida)

My son is 8, going on 9, in the third grade. I only realized his "weird" behaviors were actually sensory disorder when I adopted my daughter and had her tested last year. I filled out a sensory profile, graded by my daughter's ot, definite differences. I had him tested through my old school district but they didn't find anything wrong. I've been told that sensory disorder alone (no autism, or ADHD) is not really something the schools recognize. I have him seeing a therapist but thinking an OT would be more appropriate. We just moved out of state and he is not doing well with the changes. He has many temper tantrums in a day. I'm exhausted. I've noticed his reading level has deteriorated and wondering if this could be from the excess stress. Any suggestions?