Burn all your photos of her or you together with her. Destroy all your shared belongings or any items connected to her. Change your phone number, email, erase your Facebook. Throw away all gifts from her. Move to another location she has never been to physically.
Hold a ceremony and use your intention. voice it out loud, right down your commands on a piece of paper and burn it with the intention that the fire carries through your commands. Ask for help from your ancestors.
Especially yell out loud in your head for her to GET THE F*CK OUT- that you are THROUGH with her and are officially dumping her. Forcibly retrieve everything you gave her. Get infuriated at her. I bet you she cheated on you during your relationship and this is what led her to dump you. So get angry as hell and command her out of your etheric body because she is a parasite and is making you sick.