OK Girls Help Me Out Here ...Boy Problem.?

Okay so i know these 4 lads....Josef , Corey , Jordan and Jack. and there all my like best mates and i hang around with them a lot and one day Corey asked me out and i said ye cos hes good looking, funny and nice to me. after about a month he dumped me which was quite upsetting but 2 seconds later jack asked me out then straight after that corey.... asked me back out again. so i said i dont know to both of them. When i got home and i went on msn Jordan and Josef both asked me out as well and i felt awful and got a mive headache. And now they all want answers and its been 5 days now and they are all starting to get anoyed at me and i dont want to say no incase it ruins our friendship and they will be sad but the thing is i still like corey. So what do you think i can do? Please help me and dont say : go out with 1 for irst weekk then the other then the other then see who is best cos im not a slag! Lol okay please try to help. Thanks x