What do I do?

Is the chain too short? The pulley seems to be pulled out even when it's at the smallest gear, at the same time, it still chain drops on me when I sprint or even when I simply pedal it backwards. Also is the chain tension alright? If so, why is it that the pulley is pulled out on the smallest gear, while the chain still drops on me (only on the smallest gear), what should I do to fix it?