Who gets to tell you who you are? Or, rather, whose definition of you are you listening to? Anyone who alternates between lavish praise and harsh criticism is manipulating you. They are using their words to control your emotions, and, by extension, you. This is a highly toxic situation, which should be terminated as soon as possible. In fact, it is worthwhile to be wary of anyone who is overly generous with either praise or criticism, as either one can be an instrument of emotional control.
One way to counter this kind of abuse is to develop an honest, but also fair and loving vision of who you are and who you want to be. You are a work in progress, so it’s important to keep your eyes on the road ahead, rather than constantly looking back at past mistakes. That’s what your critics would have you do. Every day is an opportunity to live better. Don’t let your critics hold you in an emotional prison. In fact, don’t be a slave to anyone else’s opinion of you. You are as free as you choose to be.