What is he trying to say?

there is this guy and i sorta like him but then i dont. we have been friends for a year and he is cool....but things have been getting weird! lately he has been flirting with me alot! but then the next day he barely talks to me and when i ask him wats wrong he opens his mouth and says.." i....i..erica u need to no that..." then he closes his mouth and never finishes! its like that every day and its driving me crazy!!!!! i mean he can tell me anything (and he knows that) so wat is he trying to tell me????? i mean he is always there for me when i need him....so guys is this normal when a guy likes a gurl or is my friend i little crazy?