It seems like the both of you are getting yourself work up for no reason at all. The two of you are over and it is expected for the two of you to date other people. I don't think the two of you are really over each other and this is why your act the way you so towards each other dates.
Also, why did you have to help her move her bed? I think you took this as an opening to get back into her life. This is why you acting the way you did when you saw the wrapper in the garage. You two have been broken up for two years so what did you expect??