Help help help fink im depressed?

im 22 and have been fed up for quite a while now, i tried topping my self last year and in the last 3 months iv been takin alot of codiene and morphine for my spinal injury but been takin extras to basicly knock me out and calm me down abit. when iv had the meds my heart will drop between 29-34bpm if i dont have these meds then i get really angary and start hurting myself- self harm, if i dont have any of the 2 i get really depressed n upset n want to kill my self so i take the tablets n cut myself.