Vivid dreams... too soon?

Hi all,

Those of you who have been pregnant and had vivid dreams, how early did they start?

I am currently 5DPO and last night I had a very vivid dream that felt so real (the dream was nothing to do with babies etc). I also had a nap today in the middle of the day and had a completely diff dream that also felt very real, and I ended up waking up due to it (it wasn't a nightmare btw).

According to my last period, I would be 3 weeks and 2 days since it so I am still in my 2ww, very early. Maybe I'm having the dreams due to other reasons, but it would be interesting to know if it could be linked to preg?