((((((spatton))))))) I already said welcome -but welcome again, glad you found us!
Well, first I'm glad you talked to your doctor and you have a therapist. Those are both big (good) steps to take!
Sometimes it takes a while to figure out some triggers, and sometimes we might never know all of them ... sometimes it's because of past incidents (mostly from childhood) or it's a way to deal with stress or depression.
There are a lot of good resources out there that might be able to help... I'll try to track some down for you.
Edit: So I looked around... really, some of the best resources are in the pinned topic in the main forum for Eating Disorders... links to websites that other members have posted.
I hope you manage to get the help you deserve