FWB acting weird

So yesterday I sent him a couple videos around 5pm,he usually responds in good time but he replied at like 1 am. So I just replied as normal,we spoke for a little while. He said work was so busy because he's manager was off and he's the next point of call. He said he couldn't wait for his manager to get back. Then this morning he says he fell asleep and felt like he didn't get enough sleep. I responded a while later and he didn't even open the message. He's posted on Instagram since then,so I know he's seen the notification. The energy has been weird on and off. Whenever I speak to my friends about it,they say I'm overthinking it but i think my gut is telling me he's not interested anymore. This guy would constantly message me throughout the day and now crickets. If he wasn't posting at all I'd get it,but he's been active.