New Mommy, No idea

So last week, my stomach felt tight. I took a pregnancy test and it was positive, so of course I took 5 more just to be sure. All positive as well. Yesterday I had my first sonogram. The woman says, "yup, you're definitely pregnant. If I see what it is do you want me to tell you." Shocked I say yes, thinking well that's like halfway through a pregnancy. I'm 18 weeks with a perfectly healthy baby boy and just found it all out  yesterday. One overwhelmed, yet very excited New Mommy.