Does happinnes even exist?

Yes it can.Since you are at the bottom you have nothing to lose but do all the things and try new things to find happiness.There is love if you seek it.There are talents and forms of expression that make people happy.Find a big sister that has been whhere you are and let her take you under her wing and guide you.Research some mental health to see other suggestions.Pray Jesus to help you out of your depression.