Teaching all day at the wrong temperature

I feel like a real teacher now because of my field placement. I am student teaching this semester in college and I have been teaching quite a bit. I started out just teaching science to the students. Now I have moved onto math and reading. I am teaching a full day now and I will be doing it for three weeks straight. It makes the day go by quickly for me when I teach a lot. The only downside is that I do not have time to do anything. I am behind on work for my part time job. I also do not have enough time to drink water. I spend most of my day with a headache now because I am dehydrated. It is also difficult to be the right temperature. I start out my day bright and early wearing a jacket. After the day goes on the temperature rises a bit and I get warmer. I move from classroom to classroom though. I do not have anywhere to take off my jacket. I have now been too hot too many days in a row. The classrooms must be blasting their heating systems due to the cold temperatures outside. I would have preferred less heating and more cooling. I am active and moving around a lot. I do not need the HVAC system to work so hard for my day. I also think it would be a good idea for the students to be a little cold in the room to keep focus. I really need to check out the temperature on the thermostat.