Screaming toddler

My 19 month old is just being so naughty lately screaming at everything crying at everything when we go out she won’t sit in buggy or troller and when I let her walk she won’t walk with me and if I pick her up she screams and fight and pulls hair in anger I don’t know what to do I see other babies sitting behaving is it me I feel so lonely and I don’t know what to do am I falling asl a mother

Why is she so misbehaving