From what I understand, sensory overload is being super sensitive to specific kinds of touch i.e how certain fabric of clothing feels, or a certain level of noise is unbearable?

Even though I'm going through a journey discovering my own autism and relating most to the content here, sensory issues hasn't been something I've experienced. What does sensory underload feel like? Does it mean you don't feel anything i.e touch, sound, etc? Or does it look different? Or does it mean you're naturally insensitive to subtle things like social cues, subtext and what not?

Another follow-up question is is it possible to be autistic and not experience any sensitivity issue?