Feel like my ex is a "ghost"

At first, I didn't hear from him; but about a month later, I did and really didn't reply other than say "I'm rebuilding my life and wish you the best". Then he reached out to me a few other times, the last one being the day before NYE to say it would be the last time I'd hear from him "for the foreseeable future" since he was in a "committed relationship and very happy with someone I know" and "I know you are with someone too since it fell in my lap through Facebook". I didn't reply. His last communication simply said he thought my new profile pic on Facebook was "beautiful" and "take care of yourself." I haven't heard form him since although it's only been a week. So I made sure he was blocked from my phone, text, Facebook, etc. etc. I keep on having dreams of him still approaching me and I don't know how to not have these dreams. It's like he is haunting me. Does anyone have any suggestions?

Things didn't work out, you went your separate ways. Ghosting or not, eventually I guess it all ends up the same with people moving on with their lives. Based off of my experiences, it's very few people who stay friends following a relationship. You blocked this person for now. He is seeing someone else, and apparently you are with someone new, too. I would say those steps you've taken suggest that you want to put this person behind you. It can take a while to get over someone. I don't know how long you dated, or how long ago you ended things, but you had contact with him as recently as New Year's Eve which would make this whole ordeal fresh in your mind right now. Passage of time alone helps out a lot. Time to yourself helps. Time with others helps. The main thing is to keep living life, and to make new memories of your time after this person. And yes, some are harder to move on from than others, but it seems to me that you're really just thinking about him because this was all still so recent. How are things going with this new person? I would focus on that, and yourself.