There are a lot of people in that city! Do you enjoy playing Dungeons and Dragons? Finding or starting a Dungeons and Dragons group is great way to make long-term friends. It's how I made my group of local friends that I can count on for anything, and I'm nowhere near a city.
edit: Also, let me add something. I used to live in Sunnyvale. Lots of people everywhere, almost like a city. And I'm extremely extroverted, probably the most extroverted tech people I know. But I was depressed. Clinically depressed. Lexapro helped. It saved my marriage and possibly my life. Go see a psychiatrist.
Sunnyvale and MV do have lots of strangers in the small downtown strips, but that's just 2 blocks; San Jose has the inverse where the area near SJCC is always empty but people are in a circle around it. Maybe.