Dave:
Synesthesia is a condition in which one sense (for example, hearing) is simultaneously perceived as if by one or more additional senses such as sight. Another form of synesthesia joins objects such as letters, shapes, numbers or people's names with a sensory perception such as smell, color or flavor. The word synesthesia comes from two Greek words, syn (together) and aisthesis (perception). Therefore, synesthesia literally means "joined perception."
http://faculty.washington.edu/chudler/syne.html

wow Breeze, I'm kind of speechless because I also match quite a bit of what you said. 0_o

Definitely think it's worth seeing an OT, if only for the diagnosis. Try get a tailered sensory diet and home program, or maybe look into therapeutic listening for the auditory processing and interactive metronome? Weighted blankets also come highly recommended on here

All the best.