You don't say how old you are Nat, but splitting up with someone at any age is never very nice. Your first task is to wait and see if you ARE pregnant.
Apart from that, you need to keep busy, so that your mind's occupied, and also go out with anyt friends you have. I think what you're crying for, is not so much the loss of your bf, but the fact that you're now on your own again. You said yourself that you'd been arguing for a long time, which shows that there was either no communication, or that the relationship'd run its course anyway. You'll look back on this one day, and perhaps see it for the escape it's meant to be. Best of luck - x