It turns into dexamphetamine after being split by enzymes from lisdexamphetamine into lysine and damp. Vyvans isn't affected by the gastrointestinal tract so it is not affected by PH or food for that matter so OP either vyvaanse doesn't metabolize for you or you have a tolerance
Also yeah u can get high off it if you take a high dose or are intolerant to amps, although Ik alot of people when they take high doses of vyvanse it just lasts that much longer, everyone is different