Computers may be a boon but they can also be a hammer blow to the ego. Especially when Twitter is full of other author's good news. Book releases, good reviews, book deals, even another author finally getting an agent.
Your own accomplishments may seem paltry in comparison. I know mine always do! But the problem is you don't compare to anyone and you can't compare to anyone. Sit back and look at the things that you DID accomplish.
Lately I haven't been writing anything! I blogged about that a couple of months ago and it's all due to moving. And I'm STILL moving. Still in between having my own space and a new home. And when I'm not writing I always feel bad about it. Especially when other people are posting word counts and new projects.
But I have had a couple good things happen. I sold a short story to an anthology and got an estimated release date for Tea Times Three. My immediate thought is always "Well, it's only a small thing. It's not like it's going to put money in my pocket or make my name." For some reason it's always easier to downplay successes as being not big enough.
The thing to remember is that a success, no matter how small is still a success. It's something you did, something you made, that someone out there liked! Liked enough maybe even to give you some money for it! Remind yourself that you did something, and things are happening even if you aren't aware of them.