The future isn't formed yet. The past can be remembered, which is the same as saying that it can be imagined. Therefore it is the imagination. In this way the entire story around the experience is an illusion created in the mind and imagination. Whether the events happened or not at this level are irrelevant, but don't seem to be so because the mind is a great convincer!
If there is some negativity, best not suppress or deny. There is always a choice to be aware and look into any sensitivity that is being guarded and protected, any sensitivity that is being clung to as if it was something of great value, as if it was now. But time is relative, not relevant. Now is timeless, for it is now gone… now gone.
Just be aware if the past seems real. Can it be that it is a matter of "I am hanging on to it"? Expanding awareness more and more to this will come to a point of just witnessing, and this will end the clinging to the story, bring an end the conflicting thoughts and ideas entangled in different narratives and beliefs. Next what is left is the raw feelings. And then, without effort... Let it go. Now is now and for the moment, free from karma.
Just an exercise in expanding awareness.