What are you taking? and plus whenever I am on, things seem to go up and down a lot of times depending on my sleep patterns, diet, stress/mood etc... I am sure if you look at some of these you might be able to pinpoint whats going on elsewhere in your life that could be having an effect. Also, with the weight might be holding more water one day then the next. Lot of factors that play in and I hear ya when you say it messes with your head but just find out whats going on and re-adjust (also some advice after cycling a few times i dont hit the scale anymore because If i feel good and look good I dont see a purpose in what I am weighing at) Good luck with the rest of your cycle
Big