Op do you have the same routine every day (e.g going out and coming home at roughly the same times)...if you do could she be slouched down in a car further down the street watching you?
If she calls you and makes comments about your day, correct her and say the opposite, try to get her to expose how she knows..e.g
If you are home all day and age says you have never left your house all day, say something like, I've been out all day, went in to town/visit parents/shopping in another town etc
If you have been out, and she comments you have been out all day, just say to her you haven't left the house
If you have visitors and she says you have had visitors to your house, just say nobody has come to your house that day
If you have been to visit someone and she knows about it and comments, just say you have stayed home
If she knows so much about you either she is spying on you herself, or someone else is spying on you and telling her about your daily whereabouts,
Next time she comments on your whereabouts, I would ask her outright of she is following /spying/how she knows
Then after that I'd resort to the telling her the opposite from then on...
I'd probably phase her out slowly too, but that's just me, I don't like people monitoring my movements