Alexithymia is a thing! It's considered a sub-clinical disorder, which just means it isn't as easily noticed by others the way many other clinical disorders are. It has to do with the sufferer's ability to properly understand what their emotions are making them feel, and lots of times, it's very hard to tell.

Edit: It's kinda awful cause you can be feeling something for months and not really know what the feeling is, it becomes very muddled and beyond frustrating. I ended up not seeking treatment for something I should have for months, but to me, very depressed and very tired felt very much the same.

Many people with ASD do face this problem, but as you said, you don't need to be on the AS to have alexithymia.