Don't ask

What do you do when you fall in love? Keep it in or you let out by confessing? I don't know if I'm in love but why does my heart beat like when I'm running a marathon when I'm with him and it hurts when I see him with someone else. I'm probably too naive to think of this nothing will happen right? I just want to get up on my feet and finish college get a job and live life like a normal person I would be able to right?