There might have been times when you were making good progress, feeling good and confident. Suddenly, like a big bang, you felt down. This could have happened to you recently.
It’s ok to feel not so good. It’s ok to be frustrated or annoyed at times. It’s normal. As long as you get over it and move on.
You’re only human.
No one walks around positively with a big smile on his/her face all day long!