Being overwhelmed means your system is overloaded. The key is to optimize nervous system functioning so you don't get so easily overwhelmed. Sensorimotor activities are helpful but will be limited unless you bring integrity to other systems that destabilize you: nutrition, cranial/sacral misalignment, internal and external toxicity, stress and emotional factors. If you haven't read it, my book Too Loud, Too Bright, too Fast, too Tight can be of help as can my new book, Uptight and Off Center which covers all aspects of SPD. Both books cover much territory and interventions to get a handle on the problem. If you purchase them, let me know if they help you.