I am 12 weeks pregnant today and i went to ultrasound and the doctor said no heart beat and stop growing the baby i have scheduled d&c in thursday?

Early fetal demise: You should have a heart beat by 7 1/2 weeks. If you're certain of your dates or had early confirmation of pregnancy then this does sound like fetal demise. If you feel uncertain and the fetus was under 7 weeks it certainly won't hurt to repeat your Ultrasound as a second opinion. I will tell you though that if your OB doesn't do termination like most of it, he is likely very careful diagnosis