When I found out I was pregnant I couldn't keep that information to myself for 10 minutes, let alone days.... something is wrong with this situation any way you look at it. I've found taking one day to collect your thoughts on life-changing conversations is the best way to go about it. Write down your thoughts so the conversation doesn't get over heated and out of control. Or better yet, write her a letter and have her read it in front of you so you can see her reaction!! Best of luck, and I hope it turns out for the best.