Hi guys so today on my way home, whilst breaking I heard a small grinding noise, as I carried on further and breaked more I realised it was coming from one of the back wheels and seemed to get worse, at one point in the journey I had to break quite harshly and now the noise is almost constant even whilst the car is moving at low speeds dispite breaking! Any ideas what this could be? I have an early morning exam tmro and need to know if the cars safe to drive or if I need to make alternative arrangements