Anyone else feeling lightheaded?

I'm 30 weeks tomorrow and for the past four days I have been incredibly lightheaded. I went to the doctor today and he said that the baby is resting on my vena cova which is why I'm always dizzy. Does anyone have any home remedies to help me get through my work day? The doctor said I just need to lay on my side but I think, as a teacher, my school would frown upon that! Lol. Any solutions would be appreciated!