Please help!

Some of you here may know my story a bit already, but I will recap again.
I am extremely emotionally sensitive and I am mostly affected about my boyfriend's treatment of me, but yet I am unable to leave him because of anxiety.
He is often rude, proud, puts me down, disrespectful and unsympathetic toward me, which really upsets me - makes me depressed and angry, but at the same time I see somewhat of a father figure in him and I feel I 'need' his support. My father was like this by the way too - put me down and physically abused me.
So the moment it looks like my boyfriend will leave me, I start feeling this overwhealming grief and mostly ANXIETY! I am anxious about him talking to someone else, anxious about living by myself - nobody to talk to or hug when I get home, I worry about illness and dying by myself, so I feel 'safer' with somebody.
I get a lot of physical symptoms with this too - diarrhea from stress, chill and cold sweat on the feet and hands, cannot concentrate, crying, nervousness in the abdomen, so that I don't desire food, poor sleep, feeling timid.
The other day he really upset me and all this accumulated stress has caused me to snap and I kept hitting him like crazy and could not stop! That's why he wants to leave now. :(
Please tell me what kind of remedy I can take, to not feel this anxiety! I have to be able to get through this! I feel so weak!