Depression. Anxiety. Loss of enthusiasm.

There is a constant feeling of anxiety. Al tough I belong to a upper middle class family and there are no financial problems as such but still there is a constant fear of future. I am currently doing a job but not satisfied and looking for a change. But i am not able to do so as my mind is feeling depressed all the time and is incapable of doing something positive. I suffer lack of enthusiasm. Nothing excites me. I am a regular gym goer. Early i use to enjoy gym but now a days i just go to maintain myself and that too forcefully. I feel lack of self-confidence. I feel like i am lacking the motivation of doing something positive. I love traveling. But now a days traveling is also not giving me satisfaction as there is a constant fer that this is temporary and after this i have to get back to the same life. Right now i am staying alone. I am going to get married this year in November. Everything is fine apart from this depression and anxiety issue.