Macbook Pro battery barely lasts 3 hours!?

i bought the 13" macbook pro, and i only charged it 21 times, it said it should last 1000 times before the battery is weakened. it should last 7 hours, yet mine, at 100% only lasts 2.5-3. this is way too little. it should always get at least 5. btw i use all the settings to conserve energy, they dont help so much. still under 3 hours. my laptop is mint condition, practically new.