Quick response: The fear of having made things up is probably something your therapist would be okay in talking with you about.

Longer response: this fear is also something I've read about many survivors of abuse having. It's been 20+ years since I ran away from my abusive family, and I still sometimes wonder if I over-exaggerated or made things up. And when I do that, memories, flashbacks & nightmares go into overdrive - not even about the acts of abuse, but of other things. How I was always vigilant about the light under my door being broken, cos that would mean someone was coming to my room. How I always felt uneasy (read - my skin would crawl) being on my own around a family member, even though I loved them.

I hope you come to a sense of acceptance about this. It was easier to think myself as a 'loony' than to admit what happened, but until I could accept it, I couldn't live my life. I hope this helped.