Advice for nightmares?

I'll try to make a long story short, basically my ex and I were together for almost 2 years and the last 6 months of the relationship he was emotionally and mentally abusive and even slapped me a couple of times but I overlooked it out of my love for him, I became pregnant and told him and when I was about 8 weeks pregnant he told me to have an abortion, I refused so he left me and now denies that the baby could be his.

Lately I've been having nightmares where he yells at me, insults me and hits me, they've gotten to the point where I wake up shaking and have trouble going back to sleep, it happens every time I go to sleep, even during naps. It's been happening for almost a month now...any advice on how to stop having nightmares? Or at least any advice on how to not wake up shaking?