looking for picnic episode
I have searched for years to locate an episode from a TV series whose name I cannot recall. The series would be between 1964 and 1968. The episode begins with a happy middle aged woman packing a picnic basket. She has a day with terrible consequences and maybe somehow she is able to phone herself into the past and warn herself not to go on the picnic and then at the end it returns to the beginning of the day and she decides not to go on the picnic.
Any help is appreciated.