One thing I didn't learn about until I was knee deep with the first one was what I've optimistically dubbed "Mama's foresight". During pregnancy my dreams are EXTREMELY vivid, some to the point of disturbing, and I experienced worry. With almost all of them, I wake up knowing how I feel about a certain circumstance I may not have encountered before, and how I would react.
When the baby is born, these night dreams turned into day dreams for me. Sometimes useful, most of the time horrifying...I guess a mild example would be the "foresight" of falling down the stairs while carrying the baby and what horrible things might happen (and let me tell you vivid as crap). But, yes, falling down the stairs could be bad, and I was absolutely dillegent every time I stood at the top to walk down with babe in arms because of these visions. I was even motivated to take my socks off (wood stairs) in order to limit my risk.
My personal perspective is that this "foresight", worry, is beneficial, listen to it, store it in your mind, but let the disturbing aspects just roll off your shoulders.
Maybe your worry right now could be intended to motivate you into learning more about the experience you're about to go through, or to pay more attention to your diet. Project the energy you're expending on worry into productive activities.
(I don't mean to assume you are a first time mom, or that everyone experiences this Foresight to the same degree. This is just me sharing my experience with worry and dreams).