First Pregnancy

I'm about 4 weeks and 3 days. I found out yesterday, tested three times all positive test. Will test again tmm as well. (I'm a little in denial) I am very excited though. I've read a lot online that this is the most vulnerable stage in a pregnancy. I'm taking my prenatal vitamins, and drinking a lot of water. Hoping for a healthy and happy pregnancy.   I called to make an appointment with my obgyn and they made me an appointment for next month when I'll be 8 weeks pregnant. They told me I'll be getting a sonogram and prenatal visit . I'm just curious what can u possibly see on the sonogram at 8 weeks and when do you hear a heart beat ?