On mobile, screen becomes slow and jittery

On my samsung galaxy s8, i play tons of minecraft. But sometimes when i touch the screen to move around or look around,it becomes very slow and sometimes very erratic in behavior. The character wil begin to move in the opposite direction, whenever I try to sprint i suddenly stop and my phone becomes extremely jittery and i can barely control it. I don't know why this happens but it just does. It doesn't matter what I'm doing.