You're not a lousy person. Everyone goes through a time period of shutting themselves in, no mater the length. If these people mean so much to you, you're going to have to communicate that with them, weather it be sharing something deep with them or small talk or just apologizing for not being as open if you feel the need to. Anyway you can, just show how much you care. Take your time. Don't just leap in there and be all "I LOVE YOU"...might freak them out. Anyway, a lot of the stuff already said on here sounds like good ideas. Its a gradual process of opening up.
Good luck man. I hope this helps in anyway it can,