Bereaved mother

So I'm in my 2nd trimester with my 4th I had a miscarriage with my first then had my 2nd then my 3rd died at 9 months old in March in her sleep I prayed for this baby I'm pregnant with now but I feel like I won't let myself prepare for this baby I feel like I'm preparing for the worse case sanerio and I know that's not a good mind set any ideas on what maybe I can do to keep my mind more on the positive side