Expelled from school? please help?

ok two days ago at school my year 12 teacher and some career advisor (principal wasn't at school, he was busy) asked me and my mum to have a interview about my progress at school i thought they were going to say i havent been handing in assessments in time and few days not at school and late, they asked me to leave in a nice way like "this school is not for you, you should go do something better" and asked me to not go to school anymore, now my mum is angry and want to see the principal and ask them to give me one more chance, only 2 assessments not hand in time but its easy i can do it, this is catholic school btw, im in year 12, 18 years old and very angry about this situation and the two teachers, what can i do? 4 more months till i finish 12 and get my HSC