I'm rather worried...
 

One of my best friends has gone mia. I'm really worried about her cause it's not like her not to talk to me or call me or something. I know she isn't mad at me for anything, but I worry when she's gone for more than two days without telling me. I'm going to call her tomorrow, I just hope something bad hasn't happened.

Wow, that does sound really worrying. I hope you get through to her tomorrow, and everything is alright.
Hang in there
*squishes*

Make sure you are there for her, and never think you're being too nagging by calling her all the time. She will thank you in the long run.

Also, assuming you're an SIer, you probably know what it's like to isolate yourself, even from the people you love. Tell her you understand that, but you two can confide in each other safely. I hope your friend gets better!

Keep trying to call her, it sounds like a very worrying situation. Also if that doesn't work, I believe after 48 hours you can report someone as missing, so if you can't get ahold of her soon, maybe try that. I'm sorry she's gone and disappeared on you, but you have to stay strong through it. xx Laura
*edit: it could be after 24 hours, I don't want to give wrong information here..*