Overly jealous dog for no reason--Why?

I have a six year old labrador. We have no other pets, and I'm the youngest child (16). For some reason my dog constantly follows me. She has learned to open doors so she can come in my room or follow me into the bathroom. If a person touches me, she will forcefully shove them away or whine. If I'm not out of my room early enough in the morning, she'll cry on the other side of my door.

I've recently noticed she also has a tendency to sigh a lot. She lays against the couch, or if possible, on me. She'll also lean against the couch and stare/sigh until I pet her. If I go to a friend's house, she paces the house and whines (but I'm the only one she does it with). She'll also lay in my room all day and refuse to come out while I'm gone. Oddly, she doesn't do this with any of the other members of my family.

Daily things have also given me trouble. I'm unable to sit on the floor on my pc because she will literally lay on my laptop. I give her attention like I always have, but since we've last moved, she's gotten worse and I was wondering if that caused it; but, on the other hand, we've been moved in for over a year.

Does anyone know why she has separation anxiety only with me, and how can I fix it? Why is she overly jealous about family, especially since they've always been with me?