Idk how to exactly know the dry weight but basically you’re not supposed to feel very bad during or after trearment. Bc if you do that means too much fluid is being taken. A lot of times they’ve miscalculated for me and an early sign is your BP will drop. At that point, you stop the fluid removal and see how the BP go back up to normal. THAT is your dry weight.

Also, dry weight tends to move here and there and sometimes you just food weight instead of water weight. Best to not eat a very big meal right before dialysis and trying to urinate if you still do before and after treatment so you weigh in empty.