does this guy at my job like me hes 17 im 15?

Ok so I liked him and I noticed him staring at me a lot so one day I decided to tell him I liked him. He smiled at the ground and said okay and he jept staring at me and he would help me out with little stuff sometimes like carts (we work together) and everyone who I told said he was shy and that he was just nervous about talking to me. So one day I find him on instagram and it turns out he has a gf and they kiss and when I saw it, it literally broke my heart. So I liked the picture so that he would know that I knew and I now try to avoid looking at him because it really hurts ne knowing that I can't be with him and that he probably never liked me. And now that I'm not paying him any attention he intentionally does stuff to get me to notice him like walking in front of me or being in the same place as me. So I guess I'm wondering if this guy likes me or what his deal is because I thought I knew and I don't. Please help me. Give me clarity or something. Does he like me or what.