Controlling bf....depressed gf. plz help? 10 pts bst answer?

ok... I've got this bf who I've dated for almost 4 years. Me and him are very close. Months ago we broke up...and got back together about a month ago. Since then, he's changed a bit. Whenever I do not want to hear what he's got to say, or do something he doesn't want me to do... He'll put me in these situations where I'm trapped and forced to do what he wants me to do. The first incident was in my office (where i work). We were alone, we were fighting. Earlier that day I was trying to talk to him about something serious...and important. He refused to listen to me, infact he cranked up the volume on his headphones. Later that night in the office, he wanted to talk about the incident. I did not want to hear him out.... He forced me to listen. He literally held me captive IN MY OWN OFFICE, and forced me to stay there for an hour and a half and listen to his crap. He forced me to play checkers with him.. he completely went psycho... later that night he came to his senses and let me go... he walked me to the dorm where I live...then tried to force me to talk on the way there.... then tried to force me to talk to him again in a secluded stairwell there... I immediately left and slept somewhere else. Since then i've been very tense...I get very uneasy and I snap at every little thing he does to me... And everytime i try to leave the relationship, he threatens to commit suicide. He's attempted it several times before. I also completely lose it when he lays his hands on me or tries to force me to do something. Today he pulled my hair in a computer lab full of people. He pulled my hair and forced me to look up at him... he tried to kiss me... and FORCED me to walk him to the bus stop... he threatened to make a scene...so i left. on the way there we fought... he laughed in my face and i walked away. I KNOW this is a very long read... but i'm really scared... for me and for this guy... I don't know if he's going to commit suicide tonight or not... I'm scared. someone please help me :( 10 points for the best answer i promise... please no jokers... I'm really crying.