I agree with the advice given by my collegues,but felt like writing in my own words.
I might not understand the depth of trauma of failed love. What I understood from your problem above is that, a kind of pressure is getting build up every time you see a happy couple or someone gettign engaged or having fun, you actuly don't get jeleous of them , if you observe deeper you get angry at yourself which get translated into the feeling that you are getting jealous, that's why you said I "feel" jeleous in fact it's the anger on self /your circumstances / situation and feeling of hopeless ness,however there is hope for positive outcome in life.
The truth is not everyone reject you, infact if you search you will find opposite.There is lot of life hope and happiness in life . You need to increase your faith in good things in life and if you believe in God strongly believe in Him.
My strong recommendation is read some self help books, biographies of the people who have gone through worse situation in life still emerged happy ultimately.
You need to exercise strong " will power "to overcome current situation by yourself else definitly consult psychiatrist
But you dont foget to read good books ,feel free to mail me anytime.