Taking antidepressants while depressed and stressed

Hello, for the last several months I have had a real issue with stress and anxiety. It has really affected the way I function- I am always on edge, I have a lack of sexual desire, and I really have a hard time focusing or remaining optimistic. A big part may be my girlfriend, who I love dearly, but I am the only person in the city that she knows, she is moving away soon, and she is generally disspirited about everything, I think I put a crippling amount of pressure on myself to make her happy and make things great. And now I worry right when I get up, throughout the day, and when I go to sleep. I have been taking tiny amounts of viagra since I had a couple issues with performance anxiety, and I was taking Bupropion for a couple months which only served to help me from falling to painful lows, but didn't greatly improve my overall situation.

I just don't know what step to take next, I have lost my ability to some extent to remain optimistic and feel reassured. Thank you!