Melancholy

I can't help wondering whether I'm alone in feeling melancholy. Lately, I'm starting to find myself being so moody, sensitive and emotional. I could see myself seeing the world through my emotions and it can swing from one extreme to the other in another minute. Being so tuned into other people's feelings and needs, it's so difficult for me to draw myself back from others and define my own position. Also, worrying is something I do quite well and just a tendency to expect the worst. 

Am I too full of self-pity or just getting upset over apparent nothings?