I returned to work as a uni lecturer when my daughter was 13 weeks and expressed milk, still feeding now at 16 months. I used to express twice a day, about 10:30/11 and about 3pm. I kept my milk on bags in the fridge (male dominated dept so no-one said anything) and took it home on the train in a little cool bag. I expressed in my office. I would look carefully at your timetable and see if some adjustment can be made, losing form time if your secondary might help. Good luck!