I have the same problem. Sometimes my Inner Critic spouts semi-believable exaggerations or outright lies, and sometimes it has a valid point. I've been trying to manage it by asking myself, "If I was getting feedback from another person, wouldn't it make sense to do some reality checking?".

One thing my Inner Critic's arguments do is imply that I can't improve things it tells me I'm no good at or will probably fail to achieve. Now that is not realistic. With adequate effort, I theoretically could improve a situation, learn a new skill, etc.

So, where our Inner Critics are giving us a "something unpleasant is happening because you suck and I don't think you can change it" kind of message is a bit like a schoolyard bully asserting "you're a poopyhead". This is not news I can use, Inner Critic - so your argument is invalid!