Any suggestions?

In two weeks I have done 7 presentations. 5 were done in the Allied Health field. As I was presenting last night, I found myself pausing, I couldn't remember what to say about a database! And I felt like I was repeating information that I already told the students but I am pretty sure it was information given in another presentation. Do you ever second guess yourself as your presenting or do so many of them that you forget what has been said in the one you are doing? I am trying to present the resources in different orders and stopping to ask if there are any questions and moving around so that I can get students to talk back to me. Let me know what you do, other than claim age as the culprit or the frigid weather in Minnesota!