Rosies are known for things like that. Sometimes they just quit eating for no reason, and start again another time, or it may be premolt. It's probably not stress unless you did something odd and drastic to its cage, and even then they get used to things quickly.
Learn the signs of premolt. This is usually a big indicator that a molt is coming up. If not, it could just be going through a fast. If thats the case, just make sure it has enough water and dont put too many crix in the tank at a time. Just one or two and take them out after 24 hours if they havn't been eaten.