I know how you feel. I had a miscarriage and 2 months later i found out i was pregnant again. I know until you hit that 12 week mark you are going to be anxious, try maybe taking a warm bath with some lavender scented bath gel before you go to bed to relax your body and maybe it will help you sleep better. When you wake up from one of those dreams, just take a few deep breaths, and i know it sounds kinda wierd but i used to touch my tummy (well the lil bump that was there) alot just to remind myself that i was blessed enough to get pregnant again and it would make me wonder what this baby would look like, what gender, what name i would give and eventually my anxious feeling would go away. I really hope this helps