Aha! I think the fact that it took a year to get pg is a huge factor. It's only natural to fear the loss of something you want so badly, and waited so long for. Without knowing more about you, I can't explain your parents role in the dream. What jumped out at me though was that in both instances, your baby was in danger. I'm also wondering if the fact the pg has been calm and fine is causing your subconscious to show you these scenes as if to hold onto your previous fears of m/c. Perhaps the truck, bikes and dark spirit is your minds way of expressing a fear of something terrible sneaking up on you, and harming your bub, despite the smooth sailing so far. I feel like those things are a manifestation of a fear of being powerless, and caught off guard.

I hope my ramblings were helpful, lol. I just went on my instinct with my interpretation. Am I close?