New job and struggling

[Flatflatflat]

I have started a new job in a small family-run firm. Always been really good at my job and it has always given me a great sense of satisfaction.
Was asked to apply for a new role at firm by kind boss, I accepted. New role taken, old role was filled (team of 10 became team of 9, less work, position filled by sharing tasks, no replacement).
But new job nothing like I was told it would be. Dread going to work,know I will be horribly stressed or bored or sometimes both.
Working under a colleague who wanted role I have and they make pains to point out every error I make while I am finding my feet (role not clearly defined and not in a sector I have worked in before) but in a way that makes them look helpful, and me look daft.
I made a very silly mistake a month ago and they have repeatedly brought it up.
I get worked up on a Sunday as I am dreading going to work.
Do I stay as this could be a stepping stone to dream job? Or look elsewhere? Or do I stay and talk to kind boss, and tell her that I am struggling? They want me to succeed in this role and have said they are rooting for me. Advice please.

Speak to the kind boss and see if you can sort it out. Good luck 🤞

Definitely talk to the boss.

Try and plan what you are going to say without directly criticising the other person.
That is: say what is happening and how it is making you feel without attributing blame -

I know they are trying to be helpful but it makes me feel incompetent or whatever. Rather than that they are deliberately making you feel bad. If the kind boss is any good they won't need the 'intention' pointing out.

Thanks so much for your advice. I did talk to her and as you suggested I did more of the 'it makes me feel' and 'I'd like to prioritise' and I have been asked to work on projects with less feedback while I find my feet. In a nice way :)