I feel like I've already failed life....

I know that sounds like bullshit but hear me out. I'm an 18 year old guy in my first year of college and to say it is going badly is an understatement. Throughout high school I was in what felt like a fapping and video game induced coma in an attempt to battle feelings of social anxiety and depression. I was always that quiet, clumsy, naive kid who never spoke up in class. Because of this I became somewhat of a loner, missing out on all the social skills that most high schoolers naturally develop. I had groups of friends that I hung out with fairly regularly but I don't think they felt the same about me as I did them, hanging out with me out of pity. I had very poor study habits and skated by on the skin of my teeth with a 2.5 GPA, due to procrastination. Now I am at a college and am falling into the same bad habits. Meeting people is hard because so much of it is based on personal anecdotes, which it feels like I have very few of. Also I have zero knowledge of how to sustain a conversation based on small talk. During this year so far, my experience has intensified to feel more like depression. I spend most of my time on my own, and depression has made it difficult to even get out of bed, and as a result I am failing two classes. Depression is awful. It makes focusing on anything, be it school work or even other people's words impossible. Thoughts race through my mind constantly and I lie awake for hours subjected to them. This is only intensified when I smoke weed, which is a shame because I love the stuff in theory, and its a great way to meet people in college, I just wish it worked for me like it does most. I look around and see people happy and fulfilled and it drives me nuts. Now I don't mean to dump all of my sad-sack bullshit on you, I have met people here, but none really outside of my floor and whenever we all hangout I can plainly tell they don't really want me there. Jesus I am rambling.

TL;DR: I've dug myself into a few deep holes and am having trouble escaping them. I'm fed up with the way things are now, and I can plainly remember a time however long ago where none of this was a problem and I was happy. I'm not to the point where I'm considering suicide, I just don't know how to begin fighting this.