My head has a strong bad odor and teacher randomly smelled it?

My sweat has always had a strong smell, but in my head is worst. I wash my hair every other day because i know it gets damaged if i wash it everyday ( have done that in the past and hair got super dry). I took a bodily shower this morning but since i was in a hurry i didn't wash my hair. I have very greasy hair. Anyway a teacher went around smelling my head and i didn't notice until afterwards, she is a littlle bit weird like that she was checking where a certain smell came from anyway she made a face and i am sure other students in the cl saw it. So embarring. Anyway i know that when she sees me she is going to think "there is the student with the smelly head".. Anyway i don't know what to do about this problem. i wash my head thoroughly and scrub it very well but than it gets sweaty without me doing any type of exercise and i can't be washing my hair multiple times of the day.