Why cant the doctor prescribe me Beta Blockers?

i want them to calm me down ALOT and they help other problem stop getting so hot! i really benift from side effects too! apart from nightmares but i dont mind. under 18 so defo cant get and under 21 still a risk im 17 male AND CANT LIVE ANYMORE :( x can i get them from dad on my behalf? without them knowing REALLY HELP no yoga/medition i need phyiscal sympomts :( plzzz 2nd opinion from another doc? x