Help: not whole lot

[gogu]

A: How's been doing?
B: Not whole lot.

What does "not whole lot " mean here?
Help me , thanks

[Casiopea]

What about?

A: What've you been doing?
B: Not a whole lot. (I haven't been doing a whole lot.)

'a whole lot' means, not much; e.g, I haven't been doing much at all.