Dyslexia is more a reading disability that initially shows mostly in difficulty with decoding written language. Did you have problems with actually decoding the words in front of you; for instance, frequent reversals, dropping or adding of letters, consistent replacement/confusion of letters and/or letter combinations, etc. Over time, the consistent decoding problems create comprehension issues as students who can't decode the words they encounter obviously can't understand what they are reading well.

Retention of information in order to make connections is a problem often seen with ADHD. That is an attention problem, not so much about staying physically on task, but more about attend cognitively to the material at hand in order to recall and access it later.