It's natural to take a few weeks to months to get accustomed to a new role or job. Work bullies might prey in these initial weeks. They will try to tarnish your image in the team and destroy your self-esteem to enable them in exploiting you. It is also more common for senior co-workers who exploit their positions of power to show such behavior.

How to tackle this:

1. Best way is to show confidence when you are sensing such a behavior. DO NOT APOLOGIZE unnecessarily. Instead try saying "Oh so this is how it's done, no one told me this. Thanks for highlighting it, is there anything I should keep in mind?
2. Ask questions from start, be vocal. Do not let the bully think they can talk over you and shut you down.
3. These are hard things to do, some bullies are too manipulative and will corner you down. Seek mentors/colleagues at work who believe in you and build you up.

If you are someone actively being bullied:-

1. I am so sorry you are going through this. It is really hard when someone exploits you at your weakest.
2. Seek out your friends and tell them what is happening and how you feel. Sharing helps.
3. You might have to work on building your confidence for long term, but the best immediate option is to start over or a new job. Such toxic work cultures are not worth your time. If you are still stuck there and cannot because of monetary or other reasons, remember to remind yourself of your achievements and how far you have come, do not let these bullies make a dent on your self-worth, because that's what they prey upon.

There are people out there who are proud of you seek them. But the proudest has to be you :)

Edit1. I see a lot of people commenting how this is a school thing and are surprised by the term work bully. I know bullying is a big topic in schools in USA, but anyone can turn into a bully. It's the sudden access to a position of power that makes them a bully and corrupts their basic decision making skills. Example: A Supreme leader of a country in asia, just cause he is a president he believes that whatever thought that comes to his mind is truth by the god, but anyone can be a president(at least a lot of people) it does not make you special, or messiah of god himself and you should not exploit this position of power. I hope these insights helps you in understand this issue better.

Edit2. I also want to highlight if you feel baffled on how this still happens, maybe you are part of privileged group where people respect you just cause you look a certain way or are from a certain gender(Hint: most of the industries are male dominated with gender biases). Not everyone is blessed with a safe upbringing where they build up a rock solid confidence and have an amazing support structure. I hope these insights helps you in understand this issue better.