It is very normal to be listless while pregnant. However, what isnt normal, is a 14 year-old girl pregnant. While I wish you the best of luck in whatever choices you make, I also hope whatever guy got you into this situation is able to man up and provide for you and your child, if you choose to keep it.
You find yourself in a very unfortunate situation being so young and pregnant. While you may feel like being lazy, now is not the time to do so. You have much to do in preparation for motherhood. If you have to ask , "like what?" You are definitely not ready for it.