I dreamed of many hamsters.

Eating means you are doing a job. Hamster symbolizes some unexpected shocks and turns. Because it caused a commotion, it should have a bad and widespread influence. However, because it came out of the girls' toilet in a school, the hamster in the classroom came out of the front door and then you were in the last row, so it also implied that even the ominous things were not caused by you and had little impact on you. So in general, it is a lucky misfortune.