He wanted me to text him but now he won't text back

Hi everyone, so I’ve known this guy for a while from work. We had a crush on each other while we worked together, but nothing ever really happened because I was seeing someone else at the time. He asked me on a date then but I wasn’t able to go. Fast forward to now, and he’s been on my mind a lot. One night he messaged me on Instagram, gave me his number and told me to text him, so I did. He also said something about “being with me”, as if he was considering me as a girlfriend. He’s a terrible texter, and I think it’s due to him being busy, it seems like he works a lot. But, he hasn’t directly told me that this is the reason why he responds so slow. It’s been 24+ hours since I last texted him and he hasn’t responded, but he was active on Instagram.
I’m just confused because he has told me he’s into me, but it seems like he’s not invested in our conversation. Could it be that he’s just talking to other girls? I want to keep talking to him but I am not one to double text. What should I do?