Apologies if this is in the wrong place, I've not posted on this board before.
This problem concerns an ex-friend of mine. She treated me very badly when we were 'friends' but for multiple reasons, I never said anything and put up with it for many years. Then there was a straw and camel situation and I stopped speaking to her and removed her from fb etc. Initially I felt much better not having her in my life (she would constantly put me down and was extremely competitive).
But for some reason I can't let go of this red hot anger and hatred I feel for her. There will be something that reminds me of her and I experience physical symptoms associated with my strong feelings and burn with rage. I hate the thought of anything nice happening to her and at times actively wish bad things to happen to her (nothing drastic - just small things like hoping it rains on her birthday etc). I wince at the unfairness of it in that she has a large group of friends despite being quite an unkind person and generally has quite a nice life despite, IMO, being totally undeserving.
I hate feeling this way and wish I could just let it go. I try and remind myself of the saying, 'hating someone is like drinking poison and hoping the other person dies' but it doesn't help. Intellectually I know I'm just damaging myself but emotionally I can't let go. What can I do to stop feeling this way?