Distressing memories keep popping into my mind

You could try writing about that experience in detail, taking a break whenever you need to. Include the feelings you had at the time and have had since. You don't need to show it to anyone.

Trying to suppress a painful experience makes it keep popping back.

If repetitive thoughts intrude it may help to talk to a trusted friend or even a therapist about what happened.

Bad memories need management, even rationalisation, and telling someone else can help in that respect. Often there's an alternative take on what happened. Maybe you need reassurance that it won't happen again; or for someone to say you handled it as well as you could.

I've found that putting things on paper helps. I can then put it aside, go off and do something enjoyable, then come back to it a week or so later and see it from a different perspective.

It depends on what you decide to do, negative thoughts are like birds that fly over our heads. We can stop them from resonating and affecting us. Not to be oblivious to the fact, but we should remain focused and talk to God, to air out the issues going on in our minds.