Motors wont stop beeping with slight twitch

Hi everyone, I bought me a drone and has a Pixhawk 3DR MINI Flight controller, it flew great for a few days. Yesterday I wanted to fly again but I just get pre arm failure lights (two amber) and all 4 motors just beep and wont stop. I havent crashed or anything. I flew and on low battery drone then RTH and I packed it away. Any help will be appreciated. Batteries are fully charged and Flight controller starts up OK.