Is he giving mixed signals?

There’s this guy that I have been having my eye on for YEARS.. literally. I finally messaged him and we have been talking for a few weeks now just getting to know each other. We talk all the time throughout the day and the last few days, I barley hear from him. If I do it’s hours later. Now I know people are busy with school or work, I understand that. But, I’ve seen he is active on multiple different social media apps as well as is posting online (Not being a creep, we just follow each other and I see it on my timelines). Which is weird to me because we only ever talk on Facebook messenger, he has not asked me for my phone number. I think it’s bc he has an android and can see when people open messages? so obviously I see he’s active, but i don’t know.. when we do talk, he is very sweet and kind and is genuinely engaged in conversation, and then just seems so uninterested in the next conversation.

I know I should ask him what’s up but I feel like it isn’t my place to because technically we are not together and I don’t want to seem overbearing or clingy. I also know he is not seeing anyone, as we discussed that the other night.

What do you think is going on? How should I go about this? Should I say something? If so how should I word it without seeming clingy or obsessive