Lost Pet: Cooper

Circumstances

I let Cooper out to go potty around 1 am. It was super dark out and I could not see where he went .I looked for him until about 3 am. I had to get sleep so I went to bed thinking he would come home by morning. When I got up he still was not home. Please help me find my Cooper.  We live on the hwy and we are not to far from town. I'm super worried about him.