Twins AGAIN after Previous Vanishing Twin - so nervous!

Hi all! Excited and nervous to be here!! In 2013 we found out we were expecting twins at 6 weeks, but when we went back at 9 weeks we discovered one had just stopped growing and we were told it was vanishing twin syndrome. My daughter was born healthy and whole, but it was really hard on us. So imagine my shock when we went in for our first ultrasound this time around to discover twins, AGAIN. This time I'm 10 weeks along, and just praying they both stick. They measured the same and had healthy heartbeats at 176... I'm just nervous because their sacs look to be slightly different sizes and I'm probably over analyzing every little thing. I won't get another scan until 20 weeks - YIKES! Anyone have a similar experience?? I'm so scared to even think about getting attached or excited.