There is no doubt that inappropriate expectations can cause more stress and interfere with results. There really is no "textbook" case of EMDR. There is really no "cookie-cutter" reaction. To expect that "suppressed" images or events will come to mind and that these are the only evidence of "reprocessing" is not realistic. Each individual is unique. Each clinician trained in EMDR knows that some clients will simply maintain the same image or event in mind without accessing any other memories. They are trained to know whether or not processing is taking place when this occurs.
Remember that part of the preparation for each client is the instructions to "let whatever happens, happen without judging whether or not it should be happening." Just relax into the process. If you do that, without trying to make it happen, whatever needs to occur will occur. Let yourself just experience the moment. You can judge whether or not anything has changed in a month from now. This is a sufficient amount of time to evaluate, without tensing up during each moment of the current session.
If you think that there are other reasons for your insecurities, discuss them with the clinician. Remember, the first part of processing is a good clinical history that maps the clinical landscape. Only then can appropriate targets be developed.