You we’re having a nightmare, You were dreaming that regulus were destroying a horcrux. Kreacher and him went to the cave where the horcrux was found. Regulus drank the potion, the potion was obviously poisonous out there by Voldemort. Regulus crawls to the caves edge to drink water, he was dragged down the water by inferi, gasping for air as he was dragged down

i shoot up from my bed, clutching my chest, breathing heavily, I look beside me to see regulus side of the bed empty