I'm a moderate Hikki fan but some of you guys/gals take it just a little overboard.
She has the right to her privacy, she doesn't have to tell us anything.
She or her company will respond when they feel they need or want too. If something bad had happened, I'm pretty sure we would have heard it from her or from the tabloids so don't worry too much.
If she is still feeling under the weather, I'd rather she just enjoy herself and get better rather than say updating her blog every day. Of course, on the other hand she could easily be too busy to be posting anything. Finally, she's just taking a break from blogger. Bloggers everywhere are notorious for not updating for a long time.
If your concerned about TITO, its not exactly her best work and hasn't been a commercial success in the US so considering this, you can easily see that her label has definitely stopped promotion for the time being because it just wasn't worth it to them.