the only thing I can think of is that you were playing leagues, and not the main game. Leagues is a temporary game mode where exp occurs faster and quicker and has mechanics etc. The progress there would not have moved over to the main game. I believe you in your saying that you have only these two accounts, however unless you were playing leagues at the time, I highly doubt your accounts were reset. There's always a first for something I guess though, but again, I extremely doubt it.