How do I tell him I’m not interested anymore?

Last weekend I was hanging out with one of my best friends and she gave me one of her guy friends numbers and told me to text him. I started texting him and we really hit it off. He seemed like a really smart, nice, responsible guy. We started sending pictures of ourselves to each other (appropriate pictures no nudity!) He eventually asked me out on a date because he really wanted to meet me. Last night was our date and the whole time I felt uncomfortable. I was not into him AT ALL. He was really nice, but I just wasn’t feeling any sort of connection and i started to realize that we REALLY had nothing in common. After the date he texted me telling me that he thinks I’m really pretty. All I said was thank you. He texted me again saying “Well I am gonna go to bed now. I hope you liked me!” All I said was “goodnight.” I tried really hard not to lie to him or lead him on. I’m just afraid he will try to text me again today! What should I do if he does?