Not sure if it's working

How do you know when EMDR is working? Sometimes I feel like I can come to a realization that helps but lately I just feel like I'm following the ball and chewing on memories. It feels as if my brain is chugging and processing, but I don't really do any visualization unless it's just reliving the memory. Therapist checks in every few minutes but just keeps telling me to go with it. He tells me it's working even if I don't realize it. Any thoughts here?