I am sorry you had to endure this type of treatment from your parents. You are not broken, but you have been hurt by people who were supposed to care for you. You have already taken a HUGE first step by bringing your concerns here, and to begin talking about this.
The inappropriate boundaries and sexual abuse were clearly not okay, and the kinds of symptoms you are describing, bulimia, cutting, OCD, and not being able to enjoy sex, are consistent with people who have had similar experiences. For information on this you may want to look on sites like this one.
Others have also experienced similar betrayals from caregivers, which means you are not alone, and it also means there are many treatment options available to you. Therapists, particularly ones familiar dealing with trauma, will know the course this path can take and how to treat these symptoms. Here is a list you can peruse. But, since you are in graduate school, I would reach out to the counseling department at your university. Most college campuses are very well equipped to deal with the issues. If it is too uncomfortable to start talking about your parents, you can simply begin by talking about the bulimia and relationship issues. Then, when and if you are ready, you can talk more about the earlier abuse. If a face to face with a therapist is too difficult you can use an online service.
The pain you feel is likely to be coming from the healthy place inside you that knows something is off. That is the purpose of pain, to awaken us to the need for changes to make us whole again. Numbing isn’t what you want, but learning strategies on coping and evolving through this is. An antidepressant may be something that could help, but you’ll want to talk about this with your therapist. He or she is likely to be able to refer you to someone for a medical opinion.
You have already demonstrated a tremendous degree of resilience. At 28 you are in graduate school and have shown a good deal of insight into your issues and their origin. Bringing your concerns to a therapist at this point is the next best step.
Wishing you patience and peace,