I found a new guy too soon after my breakup and it's been tough mentally, help?

To make a relatively long story short, I just got out of a relationship back at the end of October. We were only together for about 5 months, but it was an intense 5 months. He was always adamant about the future he saw for us together and made me feel like what we had really was special. At the time he was pretty much everything I had been praying for and as dumb as it sounds, I think I'm still somewhat caught up on his status (d1 football player, popular, etc) even though what matters more is how he treated me. The reason for our breakup wasn't a loss of feelings, it was that he goes to military school and we hadn't seen each other for months and we started to get into disagreements about stupid little things. We only got to see each other in person for a month before we were forced into long distance, so as you can imagine it didn't work out too well. We're both extremely busy with college and it was the best (pretty mutual, amicable) decision. He said that he wanted to stay close friends and talk often- that stuck for about a month, yet he has since pretty much ghosted me (even after telling me everything was fine and that he still wanted to talk). It hurts, but I'm getting closer to moving on than I was.

Anyway, about a week and a half ago, my best friend asked me to come on a double date with her. I hadn't been looking to actively date, yet in an attempt to move on, I agreed, and we went out with two guys. Things went surprisingly well for both of us, and my guy and I hit it off well. We had a great night and by the end of it, it was clear that he wanted to see me again. Since then, we've already been on 4 dates and he's so lovely. He's 4 years older than my most recent ex (and 2 older than me), so there's a major difference in maturity thus far and I've been blown away by how well he treats me. He plans all of our dates thoughtfully, pays for everything even when I offer, has been great about communicating so far, etc. I feel highly respected by him, and he's taking things slow physically. He's super cute as well and I've been told through my friend that he thinks I'm great and is super into me.

Normally, I think I'd be really excited. Instead, I feel pretty numb. I really enjoy spending time with this guy and we're going out again this weekend. However I feel like my feelings aren't developing as they normally do because part of my heart is still torn up. On our date two nights ago, I had a heaviness in my chest as it just felt odd to be with someone other than my ex. It was a really strange feeling and I cried alone in my car on the way home. I kind of just feel like I'm going through the motions and I hate to feel like that because relationships are really special for me. This guy is obviously really great so far and I don't want to avoid pursuing things with him just because of where I'm at emotionally.

Logically I know this new guy treats me 1000x better than my ex has (post-breakup at least), and my desire for him no longer makes rational sense. It's just my heart that won't listen.

Does anyone have any advice here? I was planning on taking some time to be single after this breakup, but I guess you just can't control when you meet people sometimes.