I returned from work when DS was a similar age. I didn’t have a stay at home DP, so DS went to a nursery that was round the corner. My school were very supportive, and agreed that me going to the nursery to feed was more efficient than pumping and storing in school. I was allowed two feeding breaks a day. If you are secondary, the timetable may be suitably light to facilitate this now that exam groups have left. If you are primary, they might be able to use peri lessons like music, MFL and perhaps TA led activities to support you in continuing to feed/ pump. With only a few weeks left of term, it should be quite easy to manage until the holidays, hopefully 😊
It is in the best interests of the school too, because happy baby = happy mum = happy students!
By the time you come back after the summer, your little one will be around 9 months, so getting far more of their calories from food. This will reduce how much you are needing to pump/ feed each day, and make life a lot easier. My DS fed up to about 18 months, but for a lot of the older months it was breakfast, after school, bedtime, and then food and water (and cows milk once he was old enough) during the school day. It worked brilliantly for both of us, and no students were harmed during the process!
Good luck with your return to work! I remember it feeling terrifying just before I went back, but it really was ok!