Crack cocaine use in early pregnancy

I was in a terrible relationship with a crackhead and eventually, with much disdain, smoked crack cocaine twice. I did not know I was pregnant. I will never, repeat NEVER, smoke crack again. It was stupid. My real concern is that I smoked it probably at 2 weeks after conception and again at around 4 weeks after conception. Once I found out I was pregnant I did not touch it again. In fact, I kicked my crack addicted boyfriend out the week before I found out I was pregnant because the drug scared me and I didn't want it around me.

I've had two ultrasounds and both times the doctor said the baby looked perfect; however I know that ultrasounds do not detect everything. I had my quad screening done this month but have not found out the results. (routine genetic testing). I am now 19 weeks and will have my "big" ultrasound in three weeks. But I'm just concerned. Does anyone have any intelligent answers and information for me that does not include judging me and telling me what a terrible person I am? I appreciate it.

P.S. All the information I can find online about crack use and pregnancy is about women who use crack throughout their pregnancy. In my case it was twice in early pregnancy.