That depends upon how well one knows what one needs to learn. If you will not make that mistake a second time, you might well move on. If you think you might be lax, then carry it as long as you need.

I expect most guilt is fruitless-- wasted regret that breeds only indecision. However, I think you are the sort who learns his lessons quickly, and does not forget them.

I think, also, you're the sort who has a difficult time letting that grief go.