Ladies I can just cry my eyes out!!

Hello ladies! Yesterday I went to the doctor for my 7 week U/S. The doctor said their was no sac or no fetal pole. I thought was really odd because a week exact they were able to see both , so we were expecting to see the heartbeat. All I could do was cry my eyes out. I told her I hadn't had any spotting or cramps the entire week. She said the baby could of dissolved. Then she began to say upon conception the baby was missing a chromosome. Meaning if the baby would of made it they would have Down syndrome. I really need your prayers. I was so excited about being a mommy. How soon again can my finance & I try again ?! Has anyone else experienced this?!