<human>: Condense the text into a few key points

Been dating a guy for about a few months (4-5 I would say). Three days ago he stops initiating texts but still answers, sometimes he doesnt but it clearly shows that he has read them. 

I confronted him yesterday morning if everything is okay and he says 'yea' and I mentioned that he hasn't texted me in a while so I thought something was up to which he replies 'No. Just tired.' I respond at the end of the day asking him what he has been up to thats got him so beat but he read that and hasn't replied. I'm worried because  he usually texts me at night, just a simple 'how was your day?' And that has just stopped. 

Honestly don't want to pry but also don't understand what is the matter.
<bot>: Guy I am dating has not been initiating texts but answering some. Total change in behavior and I am wondering if he is slow fading on me and how to deal with it.