I most certainly haven't got a feeling of such major time jumps at any point of the story. Her life has been very hectic the vast majority of the time, which means it's going from hour to hour, from day to day at most, as far as I can see.
I'm pretty sure the hero big brother was on the trip to hunt the white spider for all the episodes so far, with the little brother missing his big bro and talking about him until the other students' ears started falling off. Now the big bro came back, briefly, and they met. However, the hero had to leave immediately again. In the demon lord's meeting we got two days of time before a war begins. I'd assume the hero didn't last too many days after that.