I don't see anything wrong with showering every 2-3 days, as long as you aren't doing heavy workouts or mucking out animals stalls or something between. I tailor my showering to my activity level. If I have a heavy workout, I shower. If not, 2-3 days is totally adequate.

I, too, dislike showering, even when I'm feeling OK. When I'm depressed, it's the biggest chore around. I hate getting wet in general, so that doesn't help - I totally understand the sensory overload part of it. I find it a little easier to shower when I don't have to dry my hair for something right after; it I can air dry my hair, I'm more likely to take the shower with less irritation.