ADHD medication might help. Hypnosis is, ultimately, a state of focus. ADHD hyperfixation can make it more effective for some folks, but others find it harder to maintain trance.
It sounds like you did have some hyperfixation experiences! Just maybe ones not focused on the things the session was trying to direct you towards.
It’s okay to let your mind wander and just notice the text and notice your reactions to it; “trying too hard” to push your own attention around is a normal way to get less-than-ideal results out of hypnosis. Noticing the responses you have to the words – whether they’re the ones you expect or not! – tends to lead you down an experience of finding wha tyour mind is ready to create for you.