"나한테 너무 뭐라고 하지마" Since you say "don't say what it is too much to me.", you might be taking it like 나한테 [너무 뭐라고] 하지 마. That's not the right way, It is more like 나한테 너무 [뭐라고 하지] 마. 뭐라(고) 하다 has two meanings: 1) say something (in the literal sense), 2) complain or make accusation. #2 meaning probably comes from the notion that people bring up something serious (say something) usually because there is something not to their liking. So the phrase is basically 나한테 뭐라고 하지 마 (Don't be so critical, don't accuse me) with the intensifier 너무.

뭐라 하다 is the tricky part. It means "to scold for every single action" I think the rest is self explanatory.