This is probably going to sound crazy but..

[Asparagus and Lemons]

.. Could it be possible that DD is having night terrors at this age (4 and a half months)??

Probably every second sleep she has she will start whimpering, then crying, then she will do her distressed cry before she wakes up and she will be very wound up and she sobs for a while after she has woken She even does this when she is napping in my arms

[Jellyfish]

Sounds like it could be teething. Any bumps on the gums?

[*LittleMissSummer*]

My DD woke up screaming hysterically the other night took us a while to calm her down. And she does whimper in her sleep sometimes.

I'm very interested in knowing whats happening. I just thought it was a bad dream.

[Enchanted]

Both my kids did that and I have always thought it was a bad dream too.

It didn't last long though, I always thought they were dreaming about their boobs being taken away

[UntoldAngel]

P cries at times and I was told it is just them moving through the sleep states.. I don't know if it's true, but when he screams like someone has hurt him it can't be a good thing

[Asparagus and Lemons]

It is horrible as she gets really upset. sometimes she does randomly whimper in her sleep and I understand that to be the rem stage of her sleep. But not this. its too upsetting!
Yes there are lumps on her gums. But why would it hurt while she is sleeping?