Paranoid Mummy

My son was running around the house while I was in the bathroom- he is 6. He slipped and fell backward and smacked his head into the floorboards. I heard a massive thump and came running out. When I picked him up his head flopped back and eyes rolled into his head. He came to in about 8 seconds. Emergency room, where he proceeded to vomit and be very drowsy so had a CT scan. Thank God it was clear of damage and he was diagnosed with post concussion syndrome. He is coming along in leaps and bounds now and close to full recovery- however I am struggling massively. I am in panic mode constantly watching him and his little brother and suddenly feel like I am yelling all the time. Yelling in panic ‘don’t jump, don’t stand on that, be careful, don’t dance like that!’.. I am in constant fear of him hurting himself - and even so much as when he jumps off the couch to stand up and I hear the thud of the floor boards I almost have a panic attack. I don’t even really recognise myself as a parent - I am constantly on edge, I very, rarely yell, now I am yelling... I am seeing images in my head of his eyes rolling back all the time..... How do I overcome this and how do I ever just let him be an excitable little boy again and feel he’s safe... thanks in advance