Stressed HELP!!

So i met this guy last year at a party and we really hit it off but he lives away so I didnt see him after but he came back down last week and we hung out and he kissed me (he was my first kiss, I'm 16) he is 21 years old. We hung out again after that and we constantly message eachother. Today a friend of mine told me that she saw him hanging out with another girl who also lives away( not in the same place as him) and she came down for the vacation. He is leaving soon and I told myself I wasn't going to get attached but I still feel kinda bummed. Should I still hang out with him? Should I be jealous? Btw that same day we barely talked because he said he was busy.