No Projects

I have a problem..

My manager is not giving me any work for the last 2 days and I don't know why..

She did give me projects before when it was her busiest and I don't think I'm doing a poor job since she always said "Good job", "Good work", etc.

So what's wrong? Is it just because she really has none to give me or what?

I always tell her to let me know if she needs any help in anything she's working on.

And she said "Ok"

I don't want to keep on telling her that. I'm sure she already knows that she could always ask my help whenever she needs any.

I'm rather stressed now. Is this because she really has nothing to give me or something else? I often hear that one of the common signs that you're gonna get fired or performing poorly is that you have nothing to work on.... I'm so distressed now....

Details about me:
- Recent grad -- target school
- Works in a tech company
- Analyst in a rotation program. Not M&A

What do you guys think? What should I do? Can anyone share? Do you often have nothing to do at work?

Thanks