The shadow person who lives in our house...

Okay, so ya'll might think I am crazy, but when we first moved into this house, I kept seeing what appeared to be a person walking by out of the corner of my eye. It was shadowy and happened once or twice a week. It increased, and I didn't say anything to Rob about it because I thought he would think I was nutty. I have never really believed in "ghosts." Then one night, I woke up, sat straight up in bed (was completely awake) and gasped when I saw a dark shadowy figure sitting at the foot of my bed. My heart stopped, and I nearly screamed. As soon as I gasped, the "figure" seemed to float up and away into the ceiling and disappeared. I couldn't go back to sleep, and finally told Rob about it the next morning. He actually didn't think I was completely wacky. We haven't really had anything else go on much since then. Until last night....
We had an incident with our shadow friend again. It was around 11:30 and I was coming out of the bathroom on the far end of the house. What looked like a figure went rushing by me, towards the living room (which is on the way to the master bedroom where Rob was sleeping) and I literally almost lost my balance because I stopped so fast. I thought for sure there was a person in the house, but no one could run that fast. It made a rustling noise too. The cats were both in my computer room at the time, and the "shadowy thing" was tall like a person anyway. Well, after recovering from my freak out, I went back to the computer. A short time later, my husband started yelling "hey, Hey, HEY!" from the bedroom. He has a tendency to talk and yell in his sleep anyway, so I didn't think anything of it, except that he actually sounded lucid and awake. This morning he asked if I heard him, and I said yes. He then told me that he was yelling because he had woken up and saw someone in the room walking towards him. His eyes were open and he kept repeating it as the person got closer, and eventually disappeared. After I told him that my shadow person had ran past me in the hallway (in the direction of his room) right before he started yelling, we were both a little weirded out!