Coping

I want to preface by saying that I have not been clinically diagnosed with anything other than OCD, but I am going to talk to a therapist soon to mention PTSD. I recently had a flashback to a time when I was 7ish but I saw it from third person view, I could see myself and feel exactly how I felt in the moment that it happened. Then last night, I watched a movie with family that was very triggering and it put me in a mental breakdown and I was immediately flooded with memories I must have suppressed because again I didnt have any recollection of them. They almost feel not mine but I know I was. It terrifies me to think that there are more memories, possibly worse, that I have completely forgotten about - if you struggle with anything like this, how do you cope?