A loss of a sex drive isn't always something that has to do with a busy life...many times it can be a physical condition that can only be treated by a physician. Consult your doctor if you are concerned about your libido.
Many commonly prescribed drugs, including medications for blood pressure, antidepressants and birth control pills, can interfere with sex drive, arousal and orgasm. For example, antidepressants known as selective serotonin reuptake inhibitors combat depression by increasing the production of serotonin in the brain. Unfortunately, a common side effect is a dampened sexual desire.