Is My Granddad's Spirit Making the Water Come Back?

The tide was coming back in, way earlier than we'd expected. I got it into my head that somehow, it was my granddad's spirit making the water come back. Because he wanted to drown us, so we'd join him in the afterlife or something. By the time we were back on dry land, I was practically hyperventilating. But I couldn't tell anyone what was wrong because I knew it had upset my uncle Ralph. It then just made me even worse because there was no one to reassure me of anything.