Can’t stop thinking about him...

I met this guy in June and saw him everyday for about 3 months. We never talked since we were both shy. I was so into him and he supposedly was too... but I honestly don’t see how... my friend claimed she saw him check me out and I did notice him always get nervous around me or look at me when he thought I wasn’t paying attention. The downside to all this that makes things worse is that... I haven’t seen him since August and I cannot stop thinking about him. I know he’s single and actually wants a relationship by the stuff he posts but yet I can’t reach him. I don’t have social media besides Snapchat and tried adding him but he never added me back ( I don’t even think he uses it tbh bc my friends tried adding him a while back and nothing). I just don’t know what to do at this point. I don’t know if he’ll return to work this upcoming summer where I first met him. What should I do?!? It’s so hard on me