Last night, I saw a dim object fly across the sky. It was not lit up and was moving at a fast, steady and constant speed

Last night I decided to sleep out in my backyard because I could not fall asleep. It was also a nice and clear night for stargazing too. I got out there around 3:00 AM. I setup my spot to sleep and relaxed for a while watching the stars. I know a satellite when I see one and I saw many last night. Sometime around 3:40, my eye caught a particular spot in the sky. There was an object that flew directly south to north at a fast speed. At first, I thought I was seeing a satellite. But the object was moving very fast so it couldn’t have been. The object was dim with no lights on it. I believe it was in our atmosphere because the sun would’ve been shining on it (if it were a satellite). I described to my dad later that if I had to make a guess, it was about the size of a cereal box, about 100-200 feet in the air, but i honestly have no way of knowing. The object was soundless too. I only saw it for about five seconds when I stood up in amazement and then I lost it and then it was gone. My thoughts were that it couldn’t have been a bird because of how fast and steady the object was. It could not have been a satellite because it was not lit up by the sun. All the satellites I saw in that area of the sky were generously lit up. I thought it could have been a shooting star but it didn’t change brightness or leave a trail. It wasn’t a plane because there were no lights or sound. And it wasn’t a drone for the same reason.