A different take on doubt - it is PRODUCTIVE in a way belief/certainty isn't. One of my dead philosopher friends says "Where doubt is, thinking happens. Where doubt isn't thinking stops." So moving forward may, almost certainly(ha!) does require enduring the discomfort of doubt. Perhaps even cultivating it. Certainty is not required for progress and may well impede it. How many sufferers spend YEARS being certain they cannot be helped? Doubt is good.
Actually you've mentioned three ways that doubt can work for you.
"the negative comments and help proffered by the uneducated" - this can be poisonous if we let it - but sometimes "out of the mouths of babes" or taking their words in a different context can shift us out of some pattern we are stuck in that has outlived its usefulness. If we can view them as doing their best - and then take what they say and use it for our best... that opens up possibilities beyond them or us.
"Doubt is a major red flag... to rest a while" particularly the soul killing, depressing, give it all up kind of doubt is a MAJOR signal to step back and take care of yourself. Because simple tiredness apparently won't do it:eek::D for us superwomen. So, help there. Thank you, doubt!
Third way - give us "clues" as to what we need to do to prevent future problems. When we've anticipated and been uncertain as to outcomes, we cover our bases better. Again, thank you doubt!
Strangely, I think boredom is the opposite of doubt. If you are bored with the pattern and responses, I think doubt is the only way out. Ruts are constructed of certainties, uncertainties may be terrifying, exhausting, painful etc, but probably not boring.
So, in the interests of taking care of yourself, and preventing future problems and getting unstuck: what certainty or yours needs doubting?