You are killing the clutch man. It fully closes at 1800rpm. Therefore you should avoid getting below that at all times (except when driving off from a standstill). Any time the car is driven below 1800 RPM the clutch slips exasperating the clutch wear. When you come to a stop downshift till 1st gear to avoid said slippage you are seemingly constantly allowing to happen in 2nd. It's more fun, engaging, and has the positive side effects of reducing clutch AND brake wear.