my mom is going to kill me

So just little background, I'm 18 my boyfriend is 20. I just graduated high school & my boyfriend has a full time job at a hospital making $1000+ a month. I was recently a server but I quit due to management and now I'm about to start babysitting making like $100/week so $400 a month.(which isn't too terrible) I'm 5 weeks pregnant. Me and my boyfriend live together. Our families do not know yet and I'm absolutely TERRIFIED to tell my mom. Me & my SO moved in together in march. The first thing my mom told me when I moved out was "you better NOT get pregnant" & well.. that didnt go how she wanted lol. My mom is going to hate me, she's going to tell me my life is over, I won't be able to go to college, I'm gonna be working as a server my whole life.. my boyfriends mom has all of her babies clothes, crib, car seat, stroller, bottles, maternity clothes, everything that she said we can have. So that helps. But my mom is going to kill me... any idea on how I should tell her? Need help in a bad way
UPDATE: I don't plan to babysit my whole pregnancy. I have a job interview to be a receptionist full time. Making $12/ hour. I will be breastfeeding so that cuts the cost for formula. Also, like I said we have EVERYTHING we need minus diapers and wipes which I'm sure won't cost $1000 a month like some of you are saying. Our water bill is $30, our electric bill is $90ish & we live in a paid off home. Also, I have a savings account with much money in it. So if worse came to worse I can use it. Also, adoption and abortion are out of the question . ALSO, For the other people saying "how are you going to pay for insurance" I already have insurance and they cover my pre natal doctors appts and all I have to do is pay a co pay and they cover the delivery room and hospital