Boys...☺️...🖕🏽🙄🖕🏽

How do you know if 

you like someone or not?

This is the one time i actually

can not tell at all I just can't.

He admitted to liking me when junior and he was a somphore but at the time i could not date (focusing on my studies)  and i only thought of him as one of my guy friends. However, I am now graduated and he is a senior. I have not seen him in years because we no longer live in the same state. We don't talk all the time now because of school and between his job and mine but whenever we do the conversations just picks back up how it left off. I am confused and I don't know.  Advice?