I'm tired of my dad accusing me of being on drugs when I have been clean for 3 years!?

Trust is a hard thing to regain, especially from someone you are really close too, but the important thing is to be honest with your parents from here on out. and in time your father will learn to trust you again. You might want to be carefull with medication because that can become addictive (i'm not saying that because of your former addictions) any medicine has the chance of becoming an addiction if you abuse it. You should do your research on medication your theripest is suggesting and maybe even get a second opinion or something.