You are fine. I quit smoking cold turkey cigs and weed also when I found out at 8 weeks. Now I'm 28 weeks and 4 days and my baby girl is perfect and very active. Don't stress yourself out about it. That's the best thing you can do for your baby :)
You're doing your baby and yourself a huge favor by quitting and thumbs up for doing it cold turkey, i too had to give up on my weed habit. Its all easy in the end for the little one growing inside of you!
Uhh where did you read that? My doctor told me that is not true...