why is this woman dabbling in my personal business? I don't believe she really cares about me?

I got offered a job in another city. I was unable to make it to the face to face interview due to financial reasons at the time. The company then offered to do a phone interview. Usually what follows is a second interview, however they offered me the job. There's this woman at my work. She's 14 year's my senior. After the team were told I was leaving to pursue a job elsewhere, she wouldn't speak to me. Then called in sick for the remainder of the week. She text me during her sick time off to tell me that I should be careful because my job could be fake. That job offers after phone interviews are unheard of. Come Monday morning she handed in her notice too. Once she was back in the office, she repeated that my job wasn't legit several times, and even said her boyfriend was worried. I've only met him once. The thing is, if it was anyone else, I'd appreciate their concern but I know her well to know she's not really concerned. I can't put my finger on what's wrong with her though. She's done well for herself. Lived in another country to pursue her career. She has even admitted she has enough money in the bank to live comfortably without working, and only works because she's bored. That's not all folks. She told me she wants to leave the country again but not go to the city I'll be working in, and that my best friend would miss me too much (mutual friend) if I left. What is going on?