Does he like me??

Ive been friends with this boy for a year and I'm really confused. We have sat next to each other in one class and he always flirts with me (i think). But when i met him he had a girlfriend but he acted like he didn't when he was with me. Then they broke up a few months ago and he seems more interested in me. Before school finished we would talk for ages nearly everyday and even started walking home together but now we hardly talk but that's probably because he is on holiday. A few weeks ago we decided to go out for a day, i guess it was a date but cant be sure, i just don't know how he feels. Recently when i try talk to him he just doesn't make any effort but told me when he's back when should definitely have another day out.