Did I do the right thing,I'm not sure if I did.?

I had a massive fight with five boys.I was sat with my friends on the grass at breaktime when this group of boys (Who hate me espeshialy) started circling our circle,it was ok,then one of them sat down in the middle of the circle,we just ignored him.Then they started stealing our bags,and empting them across the feiuild.We chased them,got the bags back,and picked up the contence.Then they started stealing two at time,and chucked the bag to one of their friends when we were near them.They stole my P.E bag and emptied all of it's contence,they were so irritating me so I got my water bottle and squirted water it at them to make them stop,it worked.The tallest biggest boy,grabbed,but his arm round my neck,my neck clicked and it wasn't comfortable position as he was praticley feeling my up,trying to the water bottle out of hands.I then broke free,and drenched his face with water.I walked away.He followed me,and poured water on my backside.All of my friends tried to help me,but they couldn't manage tackiling the tall one because he is 6ft tall.The others they chased of ,but they broke my friends bag,and she had to carry everything in her hands (Books,pencile case,lunch,course work-everything.) I left,and I came back in 20 minutes,they were gone,my friends said they told a teacher,and they are now in detention.I'm wondering if I should tell my head of year because I was really upset and I know they will pick on me agian,they follow me every where I go,chuck food at me,and have not respect for me at all.They make fun of me all of the time,I scared to because my friend is going out with the 6ft boy.What do I do?