At least you can name it, which means that you can identify it as a problem that you can cope with.
Guilt is a natural reaction from doing something wrong, but shame can really get people paralyzed and not be helpful. So, if you've done something wrong to offend a friend, then either make amends (and if they truly are your friends, they won't make this so difficult) or recognize that not everybody is meant to like you and sometimes different personalities are not compatible.
The other piece is confronting the shadow. TheFourQueens on YouTube has some interesting videos about this. If you call yourself obnoxious, that's part of facing the shadow, but it's important not to become so ashamed that you cannot move forward from that: why is it bad to be an obnoxious know-it-all? Are you afraid of being considered ignorant or not worth attention? Where did that fear come from? Writing all these out in a journal can be helpful, if you can get in the state of mind where you feel safe in admitting the true and hurtful answers to yourself.
Despair is another matter, different from shame, such as when you feel that you can't help people on the news. When I figure that out myself, I'll be sure to tell you, but as you must already know it doesn't help anybody for you to fall into despair.
If depression begins to affect your body clock or appetite, though, I highly recommend you see a professional if psychiatry or psychotherapy. This doesn't mean that you stop with alternative treatments, I would just personally encourage having all the bases covered because depression can be so complicated. And from my personal experience with depression, it's a terrible idea that I've seen so many times where psychiatrists write up a prescription and then ignore everything else about the depression when medication would be more effective in combination with talk therapy or just finding a more supportive group of people to have in your life.
I hope this helps!