Sick of nightmares :(

Rachelle • 23 years old, 3 years married to my childhood sweetheart, we have a little girls who's nearly 2 and due a little boy in November :)
Every single night I am either not sleeping long enough to have a dream or if I do it's always a nightmare! I had bad nightmares with my previous baby but nowhere as frequent as this and im really getting sick of it :( I'm 33.5 weeks so not too long left but I'm trying to get as much sleep as possible before baby comes and it is impossible when I'm actually worried to go to sleep as they are so vivid and generally horrifying, I can't really remember any of them after I wake up but they leave a tense feeling that lasts all day. I do remember last night's though which I will say may upset some so be warned... I dreamt I was in labour at the hospital, I was in the delivery room as labour was established and I was about 6cm. It was the same room I had my daughter in 2.5 years ago and everything seemed so real. I was bouncing on the birth ball and all of a sudden it popped and the baby's head was already out so I fell onto it and crushed his head and he didn't make it, it was horrendous I am actually still slightly shaken up and I have been using a birth ball to help with SPD and now I won't use it from fear. What the hell can I do, they are literally ruining my life at the moment and really stressing me out! I know they are just dreams but I am literally not sleeping because of them, either waking up horrified or too worried to sleep. I've tried calms to help me sleep but doesn't stop the nightmares obviously I just feel stuck :(