I was in my car driving home through the country. Nothing but empty fields and far off trees to my right. I was on the phone with my boyfriend when I noticed a huge shadow go over my car and move slowly across the field on my right. I said "what the he*# is that shadow?" and looked up and around thinking that must be a huge plane to cast such a large shadow, but I saw nothing in the sky. I started describing what I was seeing to my boyfriend, but I heard no reply. The line had gone dead. The huge shadow was shaped like a parallelogram and moved no more than 5-7 mph in a straight line towards the trees. There was no sound, no wind, nothing in the sky, no buildings nearby and no reason for that shadow to be there. I felt a wave of nausea and almost drove into the field as I was observing the shadow. Going off the road scared me back into myself and I felt the overwhelming need to get out of there as quickly as possible. It seemed like forever, though looking at my phone record showed it could have been no more than 2 minutes that I witnessed whatever this was. I sped away calling my boyfriend back as I did to discuss what happened. When I got to the end of the road I saw some dogs running towards where I had just left and they were shaking their heads funny as they ran. My boyfriend recommended that I make this report, though I have to admit I feel really ridiculous and stupid for reporting a big shadow.