twins 1 with heartbeat and the other without a 6- 7weeks need advice

just got my first true sonogram and i knew i was having twins about 3 weeks ago. Today i went to get my official sonogram and one baby measures 7 weeks and the other measured 6 weeks 4 days. The smaller one they saw the yolk and the pole but no heartbeat and the doctor was cold told me that it was going to die off. i asked if they ever saw any one come back with good news and she was cold said never and that i need to get ready to lose the smaller one. however i have read from other women that they had it turn around. can any one with twins help me I'm going crazy right now. this is supposed to be a good time and know I'm sad