Is there really no more hope for me growing taller (i'm 18)?

Maybe: If growth plates fused, no. , stretching, exercising, supplements nor dietary modifications will cause you to grow taller. Your tanner staging (puberty), bone age, general health, hormones, parent height are factors that determine your adult height. At 18 it's unlikely that you'll grow, but not impossible. A bone age will determine, growth potential and if a candidate for growth hormone.