Why am i getting so low ranked players in my normal games ?

Recently ive been getting silver and the occasional bronze players in my normals and even unranked players although im plat, it really affects my game as these players are very very bad and i cant really carry them often and the enemy team has plat and gold players. Does riot match with mmr in normals ? Can anyone tell me? my main acc is on another region so no point checking my profile.