19mth old waking up with nightmares & throwing up

DD (19months old)has been waking up anywhere between midnight & 3am with nightmares. I go in and calm her but it can take up to an hour to calm her and settle her again. And then some nights after shes calmed down she thinks its play time.

Shes also getting to the point where sometimes even she gets so upset she throws up.

Then last night we did our normal routine for bed. I went to go put her in her cot and she cling so tightly to me and started to get upset when I put her in the cot. I took her back out and took her to my room and laid on the bed with her and she rested for a while but then wanted to play. I was getting so frustrated at this point that I just put her back into her cot where she cried again to the point where she coughed and threw up a tiny bit.

I got up to her again cleaned up the cot and put her in bed with us again. She was okay until she started moving around again and then she fell off the bed! Of course I got right up to her again, tried to calm her down but then once again she was so upset that she threw up over me.

I cleaned myself up while DP took her out to the lounge to clean her up and calm her down.

3 hours after her usual bed time (7.30pm) she FINALLY fell asleep on the couch. I moved her to her mini fold out couch on the floor and she remained like that for the next 40 mins. Until she woke up again and wanted to sleep on me and the big couch. We stayed like that for another hour until she started moving around again and then woke up screaming like she had a nightmare again or didnt know where she was.
I managed to calm her down again and took her to the spare room where finally at 1.15am she went to sleep.

That was the worst we;ve had it but as I said earlier in my post shes been waking up a lot with nightmares and sometimes she gets to the point (even when she doesnt wake with a nightmare) that shes so upset she makes herself sick.

Im so tired. DP and I are fighting over silly things because we are so tired too.

I guess my question is...what should I do?