Should I be worried about this or it this normal?

I've been depressed for many years and find it harder and harder to relate to other people and empathise. Recently I started feeling that I can't bear other people's happiness. Seeing other people who are good looking or happy on TV, on social media, etc causes me pain in my stomach, makes me cry, makes me feel jealous and angry at myself, and I can't help feeling awful about my life and the way I look. I can't bear any magazines (online or offline) or images of people on youtube, twitter, pinterest, news sites etc now at all and I avoid them completely as it hurts so bad. Even if one of the few friends I have left sends me a picture of them doing something or of their new hairstyle etc it just makes me feel sad or even sick, instead of happy for them. I feel like a bad person. I have never had these bitter feelings before