unplanned pregnancy

so i'm on birth control and i was supposed to get my period last week. i didn't and then one night i randomly puked. i told my fiance and we agreed we would take a test. he said if i was that we would do it and get through it.
but the second that line showed up he immediately accused me of trapping him.
he is now saying that he isn't going to be involved because it is really his kid because he thinks i did it on purpose. he threatened me to get an abortion. he told me he hopes i miscarry. he says he is going to act like i don't exist, that he is going to move out and leave me with a $867 a month apartment all by myself.
i'm only 20. i only make $2000 a month.
i want this baby. i really do. i'm just so scared.