Bullying at work is rife. I won't number-crunch but it costs employers £M / annum, and it costs employees dearly in terms of harm to their mental wellbeing and finances if they are driven out of their job.
If you have experienced any of the following, you are likely to have been subjected to bullying:
Being made to feel worthless, inadequate, useless at your job, incompetent, making you doubt yourself and your capabilities.
Being compared negatively to colleagues, esp more junior to you, "If they can work faster/pick things up quicker/understand things easier, why can't you?"
Being isolated, disenfranchised, ignored, often as a form of punishment, while colleagues are treated noticeably fairly and courteously.
Being set up to fail, being given objectives then changing them so radically it makes your job untenable. Feeling "damned if you do, damned if you don't". Whatever you try to do, they want the opposite.
Being given authority, but then disempowered, by going over your head to your direct reports, often in front of them.
Subject to derogatory sexist remarks, designed to minimise contribution skills and qualifications. This is harassment, for which you have protection in law.
Bullying is insidious, difficult to detect or prove. It is invariably minimised by the perpetrator with comments like "I didn't mean it like that", "you're just too sensitive, can't you take a joke?", "sorry I was having an off-day".
Bullying is a form of emotional abuse.
This thread is a safe place for a handhold or to seek practical advice. It isn't always necessary to resign to escape, there are other ways. It will depend on the individual situation. You may not want to share all the details, don't worry about the AIBU dripfeed, you won't be ostracised on here if you need to keep things brief, change a few details or giving disclosure only to your comfort level.