Jrae,
Because some of my chemo was unpleasant, I find myself dreading it before I go even though, most of the time, it is not as bad bad as I anticipate (the first three chemos were a breeze because I had no anticipation anxiety). When we have had bad experiences, we assume (unconsciously) next time will be just as bad. There is probably not much you can do to keep your emotions in check other than, move forward anyways, and hopefully, be pleasantly surprised that, this time, it's not that bad. Sometimes the anxiety caused from anticipation is worse than the event!