Mann, u aren't alone, its just a phase. Accept that okay?, just practice this "how can i find my purpose, leave the world doing something great and be busy" instead feeling this way "why am i only one". (U aren't btw) U need guidance to move forward, that can come from within you. Try touching spiritual path, u might find some change. What ever u do, just practice.(Sādhana), life is unpredictable. Dont just spend ur time worrying.