Ask your doctor. They are the only one that can answer this for you. Weight gain guidelines depend on the individual person and their level of health and BMI before pregnancy.
You should ask your doctor. My non-medical opinion is that 12 lbs is a lot for only 11 weeks, unless you are underweight. Otherwise, remember that you aren't actually eating for two. Make healthy choices, watch your portions and stay active.
Re: weight gain during 1st trimester