My ex gf and I broke up?

we broke up and she moved on and wen she moved on I fell into depression and I finally pulled my self together and started living life again and now she's back msging me and it drives me crazie and I dont know how to act like I don't wanna go back in life but I think about her everyday no matter what and she's tells me she does too but I never reply to her but I hate this ***** but *** she won't leave my mind I fantasize about her sometimes and y is she msging me?