SCARED!!!!!

I've gave birth to my daughter on May 5th, 2014 who has died May 6th, 2014 because I went into labor 3 months early & plus her lungs hasn't fully develop? & my appointment for birth control is May 19, 2014 (today) . I don't know if I should go in & talk to my doctor about waiting an additional 6weeks to start my birth control , because since I had my daughter my fiancé & I had unprotected sex (twice) since then . (Yesss, I know I'm stupid for that) but I'm also scared because a couple of my relatives have told me that im more fertile after I have a child . I wonder if I became pregnant that fast . ??? its a very scary situation but also my fiancé & I are still grieving. The thought of being pregnant again makes me feel as if I'm taking the place of our daughter and I know that would really stress me out. I don't know what I should do !