I haven't been diagnosed with anything. I have aphantasia and can relate to what you said. I get sensory overload when its a sudden change from quiet to loud. When I'm stressed or tired sound tends to easily overwhelm me, lights sometimes too.
I just found out last year, and I am 24 years old. I always knew I was different and that I couldn't picture things but I didn't have a word for it until reccently. So previously I never told anyone out of fear, thought I might be broken, misunderstood, or called a liar.Rarely I can picture a simple outline, like a stick man or a couple lines but thats it.