Freaking out about conception date!

Had period 1 September to 5 September. Sex 6 September.
Had another period 29 September to 5 October. Had sex 13 October while ovulating. Had sex again 20 October. Took pregnancy test 24 October-- negative. Got terribly sick 30 October. Took Clearblue test 1 November-- positive, 2-3 weeks.
When was my conception date?