1) I said that I wrote stories.
2) I said that I was writing stories yesterday at 5 p.m.
3) I said that I had been writing stories yesterday from 5 p.m till 9 p.m.
4) I said that I had written stories yesterday by 5 p.m.
5) I said that I would write stories the next day.
6) I said that I would be writing stories at 5 p.m. the next day.
7) I said that I would have written stories by 5 p.m. the next day.