How to tell if they're no longer interested

Went on a first date last weekend and I thought it went well. I showed up late because of traffic but I kept him updated on how far away I was and I apologized profusely when I did get there. We hung out and bummed around for 8 hours which is the longest date I've ever had. I know I'm awkward and shy but I doubt he'd stick around for so long just to be polite.

He asked me to text when I got home and I did. He didn't reply until late into the next day though. Then I texted him a couple days later just to see how he was doing and show that I'm still interested in him. He replied for a little then stopped. Haven't heard from him since. Should I take the hint that he's not interested or is it too soon to tell if he's ghosted?