I'm 37 years old and 12 weeks pregnant, yesterday i went for a sonogram and the doctor ask me to retake. should i be scared.

Discuss with doc: There can be many reasons to be called back. Maybe the technologist forgot to do a measurement. Maybe one of the measurements doesn't make sense. May be something needs to be confirmed. You could call and ask your doc or just go and talk with your doc after the second scan.

Possibly: Ask your doctor why you need a repeat scan. This is often simply because the pregnancy may be too early to assess accurately.