Him leaving early does indicate him not being interested in you. But he did say he wants to see you again. He could have said that to avoid a scene or he could have been honest. Only time will tell.
Seriously though, if you were so shy that you could not talk, it's not going to encourage him to try again. Are you this shy with everyone or just with boys? Do you have boys in your friendship group?
If you want to find someone who likes you, you first have to be able to like yourself. To trust yourself and be secure with yourself. Have you ever looked for professional help with your high level of insecurity?
Never regret anything that has happened in your life. It cannot be changed, forgotten or undone. So, take it as a lesson learned and move on.