I don't know what to do 😔

So my fiancé and I had a bad argument today and after I got out of the shower, I wanted to talk about it but she was already asleep.. I get on my phone and go on youtube and about 2 hours later she wakes up from a bad dream looking very scared and since I already felt bad about our argument, I just wanted to make sure she was okay and cuddle up to her to make her feel safe.. she immediately pushes me off and it turns out that she had a dream I was raping her.. 😔 she has history with an abusive ex that raped her and she has anxiety/depression but i have never done it and never would. I tried hugging her and holding her but I was just making things worse. What can i do? I love her and just want to make her feel safe with me. This is the first time this has happened in the 14 months we've been together...