그러다 comes from 그리하다 and means "to do like that" (active verb), don't confuse it with 그렇다 (to be like that) which is an adjectival verb. There is also 이러다 which means "to do like this" (again, don't confuse it with 이렇다). Note: conjugated form is 그래 not 그러. 자꾸 그러면 나 화낸다! If you continue like that I'll get angry! It's also used to mean "to say like that". 내가 그랬어? Did I say that?