Question about my health respond FAST!!?

okay bit scared and worried im 14 and had blackout yesterday because got up too fast and heat and i fell hit a door i only blacked out for 5 seconds but i hit my head on door got a welt or bump but today i got a bad nose bleed for about 2 to 5 mins not too sure but it wuz just coming and coming out oozed out my other nostril a bit and when i propped my head up in a regular position blood like evacuated fastly from my nose to my mouth but only spit out like a handful of water if u can picture that now is that just maybe out of nowhere or part of wen i fell and is there symptoms i hit the back left side of my head and btw i have NO memory loss i still remember everything i did before i fell