How to get over being a wimp?

so i've liked this guy since october and he flirts with me all the time and shows indication that he likes me back, but he's a flirt. So how am i supposed to know if he acts like this to other people. He acts like he likes me and he's been showing more and more indications lately like slightly opening up about family issues and visiting me and my friends when we have free time in school. I talk to him all the time in person but never not in person. He has my number which i'm not even sure is right because my friend gave it to him but he never texted me. On facebook we've talked on like public things before but on chat i just stare at his name and like no one ims each other. How am i supposed to know if he's just being a lead on or i have a chance? I need to be able to have some kind of outside of school relationship with him soon or i'll go all summer with out talking to him and that won't be good. I'm just scared of rejection. and if you think i should move on how?