I’m just scared that, if that’s really how it goes, I might become compromised and depressed, and end up a sort of gloomy moralist.
I don’t know, I am sorry, of any saints offhand who doubted their actual chosen and effected vocation, which does not mean that such saints do not exist. Certainly many of our saints have suffered deeply for one reason or another and for a very long time in their chosen vocation, some even to their death bed. We can be totally sure and trustful, confident, that where God permits suffering, He also provides the necessary Graces to endure same - as you rightly point out.
Your probable best path is to seek spiritual direction and in this situation, you will be able in hope to open up completely to the director who can then accompany and facilitate your discernment journey. It is not always at all a quite straight path of being sure of one’s call - it can be a very windy road with many matters needing discussion, addressing, perhaps even overcome. Catholic Discussion sites such as CA here can be a wonderful resource indeed - sometimes however where quite personal matters especially are concerned they might add to confusion with different opinions put forward.
This Jesuit article might assist, while your best path is spiritual direction
Quoting from the article:
“Clearly, engaging in a good vocational discernment process can be a tricky, often challenging business that can include periods of confusion, doubt, and uncertainty. Dealing with the questions that inevitably come up requires skillful discernment of spirits. That is one reason that daily personal prayer, frequent mass attendance, and regular spiritual direction are essential components of the decision-making process – especially in the final, often more subtle stages.”
God bless you and bring you His Complete Peace in your discernment journey.