Am I going crazy or is this a sickness?

I live alone, a bachelor, and do pretty well for myself. I read that depression and anxiety can do things to you but I am pretty happy. But weird things have been happening.

1. When I'm sitting in my room out of the corner of my eye I see a man walk up and look in from the doorway, but when I look to see there is no one there. It's been about two months now and it's happened like four times in three different rooms.

2. When I get up at night be it to take a leak or get something to drink, naturally it's dark but on two occasions I can feel something there, like an outline, like when someone is trying to sneak up on you but I reached out and nothing but air but I felt something was following me.

3. My den is downstairs and a living room both on opposite sides of the kitchen and dining room, I wanna say three occasions I walked passed the kitchen on my way from the living room to the den or vice versa and clearly saw a small man standing there but when I stop and look back there is nothing there.

4. Lately I've been experiencing that thing where you dream that you trip or fall and your body jumps and it feels like you fell so it wakes you up. It keeps happening almost every night, not so much a problem because I think it's actually pretty cool but still I don't think it should be so constant.

I know my house isn't haunted, it was built in 2002 in North Las Vegas, NV. I've been getting more and more paranoid lately too, I find myself getting home and I check the backyard and the whole house, don't know why just do. Now it's starting to freak me out and possibly starting to affect my social life, a few buddies came over earlier this week, we knocked back a few but I found myself on the verge of asking them to stay the night, I know I'm a grown *** man.

I have no significant problems in my life, my parents are healthy, my brothers are doing good, my nephews are all fine, business is booming, aside from number 4 I have no trouble sleeping, I'm in good health, I can't find any reason. This has never happened before. I figure it's maybe because I'm in a new home but I've been here for about 7 months now and it's been peachy until the last two months.