Am I liable for sin and expiation for breaking my fast when in doubt about the entry of Maghrib time, or for drinking during menstruation when in doubt about its onset, and am I afflicted with waswas (obsessive whispering)?

The questioner must make up the day she broke her fast if she was unsure about the sunset, because the default is the continuation of the day, and it is not permissible to break the fast unless one is certain of its setting.

As for the brown discharge (al-kudrah), if it appears before Maghrib, the fast of that day is invalidated and must be made up. If it appears after Maghrib, the fast is valid.

We advise the questioner to avoid obsessive thoughts and not to pay attention to them, as her feelings of addressing (herself) and her doubt about swallowing water during ablution indicate this.