Is he not interested or just busy?

I met up with a guy I met online and it went super well and we both agreed we should hang out again. We hadn’t talked in a few days when I asked for his Snapchat so we could talk outside the dating app (I asked in the evening). He gave it to me early the next morning and I added him several hours later but he still hasn’t added me back and it’s been almost a day now. Is he busy? (He is a college athlete and works and takes classes too) Or should I just give up and assume he’s not interested?
Is he not interested or just busy?
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