I guess, Whistler's goal was to convince Angel that there are multiple futures, and he, Angel, can change the future of (in?) this particular timeline.

(Or maybe there are different dimensions and this Angel is from a another dimension where Wesley is still alive and he every day begs Angel to find a shrink.)

In any case - where is "our" Angel? Has she been thrown into the future on into another dimension?

I admit, all these time-travel, dimension-hopping puzzles make my head hurt.