I was just about to write a post about this until I thought it best to check to see if the topic had already been covered....and lo and behold.......
I think you're right to make a distinction doubt and confidence. I also think they are deeply interrelated: You need one to temper the other. It should be mentioned that perfectionism is a sympton of Low Self Confidence as well, and perfectionism can be utterly, utterly destructive. I wince whenever someone Say "Perfect" or "Perfection" because I know where the true meanings can lead.
Basically I think that having properly balanced levels of doubt and confidence is the most important factor in any writers chances of success. It permeates everything:
- style (Am I confident the reader will like that simile or do I need to change it?)
- plot (Am I confident the reader will link together the plot or do I need to add more exposition and/or scenes?)
- editting (Am I improving this sentence, or am I just changing it for the sake of changing it?)
- receiving feedback (Am I confident enough in what I'm trying to do to reject this bit of feedback as subjective opinion?)
- even actually finishing the damn thing (Am I confident I've done everything I can?)
I'm actually at a similar situation, but slightly more removed. None of my friends really read in genre I write, and even then I probably wouldn't believe their feedback because, after all, they may just be saying positive things out of friendship. So I've got one piece of feedback I'm not even sure I believe....handy that. The situation is worsened by the fact I won't join a writers group, in part because of shyness, partly because I don't think I could contribute effectively, but mostly because I don't think I could fundamentally trust the feedback they give, and also that I don't have the confidence to manage that feedback positively. But that's a personal issue I have to deal with.
A lot of people, unfortunately, will blow a lot of smoke up your arse simply to convince themselves it's worth defeating their own self-doubt, and so a lot of feedback you get is like a bad pep-talk from a demented uncle who's only watched Glee for the last 12 months ("Believe and it will
happen" - what a load of bollocks). As a consequency, all feedback start to sound hollow and that healthy blend of self doubt and self confidence starts to become imbalanced (Conversely, you can get pulled in by the praise and the boost in confidence also imbalances the Doubt/Confidence mix).
Anyway I've gone off point with a bit of navel gazing:
What I'm getting at is: judging what you say you've got a perfectly acceptable level of self doubt - it's actually confidence you need to look at. But don't look at me - I ain't got any....hehe