Hey there, Shivam Dabas!
Unfortunately, the other guys are totally right and your external HDD is failing fast. After you've backed up all your data from it, I'd recommend you contact your HDD manufacturer's customer support and send an RMA request. Since the external is fairly new, it should still be covered by the warranty and they can provide you with a replacement product. Refer to their official website for RMA process details.
Best of luck!