my FH and I don't even have an official date and have kinda put the brakes on the planning for now, but in the beginning I TOTALLY had dreams like this!!!!
I dreamt like my dress was missing, and that I had to wear one I didn't like, and that everything that could have gone wrong did! It felt like it was disorganized and nothing was ready. scarry dream.
*HUGS* I think it's normal to have anxious dreams, especially since this is an important day for you. You're probably just nervous that everything will work out as planned so your subconcious is letting those nerves show through in your dreams.

Hope that helps a bit. You're not alone.