Confusing situation, please advice?

okay so about a week ago a started talkin got this guy online and i new it was safe and all cause he had lke 500 picturres of him on myspace so i new he really was 15, and he was really nice. he wanted to call me so we started talking on the phone. i didt think anything would happen but he said he really started liking me, and i said it back beacua ei feel so bad saying no to anyone. he told me he loves me, i said it back (i wish i hadent but i couldnt halp it). im 14 and hes 15, and im starting to see the other side of him. he is very jealous and obsesive. he told me hes never going to find another girl untill we meet, and were going to get married and all this stuf. everytime a guy comments me on myspace or picture comments me he gets reaalllyy jealous. every singe night were on the phone he cries like crazy cause he thinks im going to find someone else or im just gunna stop talking to him. i told him wouldnt. he recently told me he tried jumping off a building before. the thing is