Does sperm release due to wet dreams invalidate fasts?

Today morning I had a bad experience in my life and now I want to understand whether is it ghuna or not. I didn't eat anything in sahri I slept without doing sehari and after that I had a bad dream and my sperm was released automatically. When I woke up in morning I found this out, so I don't no what to do now as is it ghuna or what exactly it is as I didn't do it intentionally.