Scary/vivid dreams early signs of pregnancy?

So I feel kind of stupid for asking this, but I was just curious if anyone has heard about or experienced nightmares and/or vivid dreaming during early pregnancy? My husband and I are currently TTC baby #1 and I'm in my tww (af due 2/9). The past 2 nights I've had nightmares, and before then I honestly don't even remember the last time I had one. My dream last night was pretty terrible and I kept thinking about it all day long! I read on a couple of different websites that vivid dreaming or having nightmares could actually be an early pregnancy sign!? Anyone else ever heard of this?