Hello ladies! So, I just found out I was preggo about a week ago and I have no idea what to do!

I haven't told anyone yet(except my fiance of course!) so I'm feeling a little lonely

I'm 19 and still at home, so I'm not too sure how the folks'll take it, especially since I'm the youngest in the family and the first to have a baby, but I'm sure they'll be happy in the long run! But, until I tell them, I need advice: How do you plan for a child when you've been one your whole life?!?! Anyone?
PS~Anybody else having constant cramps? A little scary...