Help me! im coughing up a little blood!:(?

well im 14 and i was eating this gobstopper, i could taste blood in my mouth so i got a tissue and coughed on it, and there was abit of blood on it, and i coughed on it a few times again and there still was some there, and i also did like 10 seconds, i have no cuts in my mouth i have checked, and i told my mum and she said, ill see how you go:(! help