What should I do with this stray dog?

I found a stray dog walking down the street and it kept following me. So I opened my door and it got in my car. I saw that the dog was neutered with no collar and took it home. I gave it food and water and tried to take it out to go to the bathroom, but it just kept sniffing. So, I tried to lightly pull it back into my house and it tensed up and stood its ground outside. So, I had to pull extremely hard to get it to come back in. It keeps staring at my front door, wanting to go outside. He still hasnt gone to the bathroom and I was wondering what I should do? Is it acting like this because it has an owner and doesnt feel comfy with me? He smells really bad :) Should I try and take care of him? He doesnt like to be lonely inside the house and follows me everywhere I go. Im probably going to take him to the humane society today. Help me out guys.