What has happened to my sister?

[girl]

She used to be outgoing, talk on the phone most of the time, draw and rarely goes on the computer. But now, she stays on the computer for the WHOLE day, I rarely get to use it now. When I try to do something on it, she gets mad and tells me to get lost. I don't see her talk on the phone anymore, she rarely goes outside, doesn't want to come outside to restaurants so we can have a quality time with our family. She has gain a few pounds,but she is not fat. All I see her do is be on fb,twitter, surfing the web, playing games,read stuff and so on. She doesn't chat on fb or twitter she just see what's going on. What happened to the girl I used to know?