I think I have only rescheduled one time, it was because of a meeting that I needed to attend at work. There was one time when my T was considering rescheduling my time so a client that had been taking a break could come back ( at my time) but after a discussion she decided not to do that...she knew I was right
As far as wanting to reschedule due to my own anxiety or because I was projecting about a session; I have many, many times felt like " oh my God...I do not want to deal with this today" or I would be too embarrassed to talk about an issue that I had emailed to her, and emailing is a great ice breaker for me But once I am in the room, sitting on the comfy sofa I start to feel more relaxed as we begin a dialogue. I think what you are feeling is normal...just go with it and allow the process to happen good luck to you!