I've been feeling kind of down, what might this be?!

So I've just turned 21, and I'm feeling pretty horrible right now. I struggle with anxiety, sometimes to the point where I avoid places that I know are going to be crowded, and if I do end up there, I get dizzy, shaky, etc and sometimes end up leaving. I've also got a fear of flying on an airplane so severe, that anytime I'm driving or a passenger in a car that's going at a high speed, I suffer severe panic attacks. I've also been hit by realization that my social life is downright horrible, and it's mostly my fault. I haven't spent time with friends for over a month now, and as a 21 year old male, I've had one female friend, who was only a friend for about 3 weeks. I'm always negative about myself (not on purpose, it just happens) and I can't control what I say and do, and sometimes in a social situation I either go really silent, or say things that I know will make others mad (again not on purpose). The past few weeks, I've been binge drinking on my own, about once a week, which makes me feel better for a while, but that much worse later. I'm a college student, and my grades seem to be declining with everything that's happened. Also, in the past 5 years I've been diagnosed with Juvenile Diabetes and been in a car accident which should've killed me, but I managed to walk away with no injuries. These negative thoughts just pound in my head, and I can't shut them off. I've had the anxiety for about 2 years now, and it sometimes seems like it's getting better, but then comes back more severely. Am I depressed, or maybe Autistic. Do I need help, and should I get it soon?