She sounds extremely toxic and I'm sorry that you are going through this. You are grieving the loss of the relationship and the fact that she deceived you - you sound depressed, understandably. It will take time to get over her, but you can get through it. Try not to obsess about it and when you do reflect back on it - remember the negative parts of the relationship and not just the "good times."

If you continue to feel really down and have trouble moving on ... I think you should see a doctor to see if you are depressed. Seeing a therapist may help you as well. You can get through this but you may need some help.

Try to stay away from Facebook if it is too triggering for you.

Take care.