How to i get my hair to get back straight?

hi, my hair is relaxed, its been for like 5 months, i condition it like ever 2 weeks but every time i wet it..goes back natural( and i am not mixed)i normally just pass a pressing iron through it(tht rotating hot iron thing) but i think my ends are thinning out...what else can i do to get my hair back straight after i was and condition?... it even goes natural it like i go out and rain drizzles on my hair