Have you had her eyes and ears tested?
My son had to get glasses at 18 months, and up untill he did he was the crankiest little boy in the world.. frustrated because he could not see.. and we did not know... I felt we needed to do something so I went for all his checkups, and more... got his eyes checked, ears, speech... and trust me it is all connected. I dont want to scare you at all, I just want to let you know that there has to be a reason, no matter how small you think it might be, that your little princess is moody.
Could be teething, could be feeling lonely, could be that she reached the "mommy" period where she wants you at her side 24/7.
But, observe her, see when she is acting out, make notes. Call your pediatrician and give her/him all the symptoms and tantrums. It might be something you have not thought of.
I just learned my son has sensory issues and has difficulty communicating... that in itself must be frustrating. So the tantrums still continue.. but not as much as before he got his eyes checked..
Hang in there momma, it will get better.. talk to your pediatrician, and make appts to get her checked out.
For sleeping, make sure her room is nice and dark, maybe turn on a fan.. the white noise calms them.
Hugs