freaking out

Hello I'm Taylor and I found out I was having twins yesterday (they almost missed it)I'm 6 weeks 3 days. The ultrasound tech. Told me that I either have mono-mono twins or mono-Di twins. She says it's to early to tell but seams to be leaning more towards mono-mono. Dose anyone have these twins? How has your pregnancy gone? Should I be freaking out I read in one artical that it's a 50/50 chance that they will live. What do I need to know?