Your answer is in your own post...quit being a big bummer. I was 19 years old and I went to party...The guy who was having the party told me I was a bummer & I whinned too much... so I was not invited... I had a big aha! I figured that there must be something I could change about myself... So I changed that about me... I decided the change was to change my conversation style. I began to try to tweak down my negativity talk so I might become someone that somebody might want to come to their party..I figured right....I don't go to parties very much any more...but I kept the attitude of being fun & tempering my negativity talk... It helps to smile... Start off most conversations on a positive note...If you bring up negative things later...make sure you keep it to a minimum...
Maybe your girlfriend is already gone...but you can werk on you...
It didn't take me long to change...It was almost instantanious...
Give it A SHOT...