Does my guinea pig sound scared of me?

I've had my guinea pig for 2 days now. I've held her least 2 times per day since I've gotten her. Temporarily, she's in a storage bin with holes cut in the top until I can get a wire cage with a play pen surrounding it. I reach down in and get her. She runs a little, but when I get my hands on her, she sits still and lets me pick her up. I sit down with her on the couch, and usually she sits in my lap with her head sitting in between my legs. She makes low squeaky noises, almost like shes talking to herself. I rub my hand up her back and she makes a rumbling noise. Is this okay? Whe I let her just sit there, she doesn't try to run off. I even sat her on the couch beside me where I wasn't touching her. She made a really high pitched noise them ran behind my back. When she's sitting on my chest, she climbs up and sits on my neck and lets me pet her. She shakes a little bit...and bites her teeth together...is this a bad sign? And please, if you know f anything that will help her get used to me quicker, let me know. She's so darn cute and soft. I want her to feel comfortable with me so I can hold her more.