New pregnancy fears 3 months PP

Amy • Mom to Emma, Garrett, Evelyn and Bennett here and my Elizabeth in heaven.
I lost my beautiful little Elizabeth Michaeli on September 4, 2016. She was stillborn at 42 weeks. She had a true knot and the cord wrapped around her neck twice. I went into labor naturally and had no idea she was gone. She was just gone. Born beautiful and perfect in every way. Lizzy was my third baby; my first pregnancy since marrying my husband in 2015. 
My grief has been so horrible. My daughter and son (5&3) miss their little sister they so looked forward to bringing home. I haven't been myself and so distant to them, trying to connect and show them I still love them, mommy is just sad.. But I feel like I'm still failing them. 
December 12th I found out I am pregnant again. Due 11 days before Lizzy's due date. All I have wanted is to be pregnant again. Now that I am, I'm so torn and conflicted. I'm 6w3d along now and all I can think of is that I will go in to my doctors office and have them tell me this baby is gone as well. 8 months is a long time to continuously fear my baby is dead.. I'm so afraid I won't be able to bond with this beeb because of my fear.. 
Here it is Christmas, I don't want to celebrate. I'm horribly depressed and full of anxiety.. I'm an absolute mess..