My 18 month olds behaviour has been awful the past month. CONSTANT screaming, full-on tantrums, screaming at everyone to "go away" and constant hitting. She especially hits me. I have tried ignoring it- she keeps hitting until she gets a reaction, time out- she just comes out and hits me again. She hits her sister and pulls her hair for no reason. Is this normal? Any tips? My first daughter was nothing like this!!!