The Horror Expert by Frank Belknap Long

Ralph Gilmore could not escape from the nightmare. There was no escape anywhere, for his world had become star-crossed with dark patterns of betrayal and outrage that hid the light of the sun and turned the still wet, slippery pavement beneath his feet into a quagmire. He experienced a sinking sensation, a hollowness at the pit of his stomach which forced him to take refuge in his room and even there he could find no peace.

It was impossible to avoid remembering, impossible to keep the tormenting events of the past two weeks from screeching, roaring, clattering back into his mind like an onrushing subway train, its red lights ablaze. A jostling on the platform, a violent shove and he was lying directly in the path of the train, glued to the rails by blind terror. Only -- the rush of returning memories was worse than that, much worse. If it had been merely physical, if it had been merely something that could crush and destroy him he might have welcomed it. But there was no escape from a horror of the mind, unless drink or drugs could be used as an anodyne and something deep in his nature prevented him from taking that dangerous road to forgetfulness.