missed miscarriage and a D&E

Hi everyone
A couple weeks ago I went in for my first ultrasound just to find out that there was no heartbeat. I was supposed to be a little over 10 weeks but was only measuring 7. I had a D&E last week, and was wondering how long everyone else who had a miscarriage waited again to TTC. I'm so afraid that it will happen again. Also, since my body was still trying to hold onto the baby and it's heart wasn't beating for 4 weeks before I got the D&E done would you say that it was likely that the baby just had a chromosomal disorder and it wasn't anything wrong with me such as low hormones or something? Any advice would be appreciated thank you.