So these jerks at lunch pissed me off today and...?

Today in lunch these idiot freshman guys next to me started pushing their table into ours. When they rammed it like 10 times i got pissed and stood up and started cussing them out (i never cuss and im usually conserved so it shocked them) they quit for a bit but then started throwing stuff at my friend and calling her fat ***. When they spit on her i got up and started to go over to them but got stopped by a teacher. They didnt even get in trouble. If they do it tomrrow what should i do?