Internet communications are much more fluid and asynchronous than conventional phone calls or face to face conversations. People pop in and out all the time, don’t respond for long periods of time, and don’t always say bye for various reasons. What you said was fine but all you needed to say was something like “I gotta run, it was good talking to you.”
I think you should chill. . . but, it sounds like you’re not sure how he feels about you. Maybe you should find out if he feels similarly about you, but do it in a subtle way, and then adjust your expectations.
You … JERK!
So, I have this friend who was living in Minneapolis. About a month or so ago, he texted me to let me know he was moving to D.C. in a couple months, he’d gotten a new gig. “Congrats!” I texted back. “You must be stoked.”
I didn’t hear back from him. No big deal, he’d probably gotten involved in something else and there really wasn’t anything to respond to. I didn’t think a thing of it.
A month later, I get the reply, “I am.”
So I said to him, WTF, are you seriously just now answering a text from a MONTH ago? Dude, I don’t think you understand texting. He sent back LOL and I continued teasing him about it. Finally, I started telling him a joke: “Why does a chicken coop have two doors?” He texted back, “Why?” I said, “Fuck you, I’ll tell you in a month!”
I hope I remember. In about a week or two, I’m going to text him the punchline. 
(Because if it had four doors, it would be a chicken sedan.)
Find a spot with a little privacy and have a good time.