My 7 week old baby just screams at the same time every night for about 2 hours. I know he's not cold/warm, dirty or hungry and he doesn't have trapped wind. I do make sure all his needs are met but still every night without fail at 6pm he will scream. He doesn't arch his back or clench his fists so I don't think it's colic but what else could it be? I'm loosing my mind.