I am not sleeping at all for the past 3 days, trauma from my sociopathic ex gf who mentally and physically abused me 3 years ago keeps upsetting me as I am finally in a healthy good relationship with someone else, how should I deal with this?

Sleep hygiene. Do your best to maximize your opportunity to sleep through self help sleep hygiene measures like avoiding stimulants in your diet inbthe evening, etc. Also consider talking to a therapist or physician about your concerns regarding your abusive relationship. Sleep is essential and going more than 2-3 nights without sleeping well can cause all sorts of physical and mental issues ADDRESS NOW!
Counselling. If you still suffer from this past event, you need psychologic counselling else your current relationship may be adversely impacted.
What you describe. as sociopathic sounds more like borderline pesonality, or worse. Consult a mental health pro for clarification about what your ex is doing and what that might really mean. More importantly, what can you do to protect yourself? You sound too vulnerable. True?
Therapy? Have you yet tried any form of psychotherapy? Typically, the optimal combination of things to treat emotional issues such as anxiety or depression is medication (which, on your best day, is supposed to take the edge off symptoms) but the real gruntwork takes place in psychotherapist's consulting room.