Clearly, they are hazing you and yes, you MUST assert yourself, otherwise they will eat you up alive.
First thing - tell nothing about your personal life, your health or your emotional problems or your family and do not let them see you stressed out or confused.
Second - go to your boss, obtain a copy of your job description.
When you politely tell these people F off, you must know what your duties of the job are and perform them flawlessly.
Here is how I handle bullies and assholes at work:
I say things like :
- This is a really great suggestion you have, I will definitely consider it ( and then do what I want anyway)
- I d love to help you, but right now I am working on a specific item I am expected to complete by my supervisor. ( and then not do it until I have time. I will ask if this person still needs help, but by that time they have been stewing already and have completed the task themselves. You asking if they need something, makes it look like you are a team player and if that person bitches to your boss, you can say: I offered, they declined )
- when the pushy person doesn't get it the first time, I will say : " I would appreciate if you could respect our creative differences. I know you have experience in this area, but I am personally held responsible for x, y and z and I am definite on my decision to do it this way. "
Every time you confront someone or push back you need to have arms open not crossed, make strong eye contact, have a medium tone voice and have a pleasant expression and or a smile.

When these bullies see that you are not going to submit to their snotty behavior, they will leave you alone.

If you have any questions about operational flow of your department, you need to go to your boss and clarify your role and duties in the dynamic.
Your goal is to make these people your bitches, not the other way around or ,at the very least , to get them to cooperate with you because you WILL need them someday and you don't want to make enemies.
I also openly Confront people in private after I have gotten them to at least treat me as an equal. One woman at work is a particular bully,
But I took her aside and was able to tell her how I feel about her.
I usually say something like - I value your knowledge and expertise, I consider you an important member of the team, but there is something that has been bothering me and I wanted to talk to you personally instead of gossiping behind your back or running to the boss; I wanted to know if I have done something to offend you, because I ve been feeling like x, y and z. My goal is for us to have a good team and help each other."
Most of the time it will do the job. Very rarely the person is completely
Toxic and needs to be written up and fired, so you have to file an official
Complaint with your supervisor.

I hope you can figure this out. If you have a good boss, you should probably bring up your concerns in the way that you are looking to better integrate into the team and to clarify your work duty expectations

Wow Aronia! Great answer!

I suspect it's really the culture at your office and that's a hard thing to change and to address. Is the secondary sales staff like that to all the BDC reps or just you?

Are you supposed to go directly to the head BDC rep for problems? Some departments are structured like that, where they'll have a senior position who handles issues, so that the manager isn't bogged down. If that's the case, then you may have to just suck it up and send issues to the head rep. If that's not their structure, you can go to whoever you want to go to.

Sometimes just saying, hey, if there's a problem with my work, lets talk about it., can help. Be calm, be polite. Sometimes people are often so disarmed by that that they literally just get off your back.

But honestly, it wouldn't surprise me if this was just one of those dysfunctional work settings where no one ever deals with the jerks and so it's like the inmates running the asylum.

No, I'm supposed to go to the manager. The head BDC rep is there for scheduling and that kind of thing; she's just been there the longest. I'm the only other BDC at this point because all the others quit. The other BDC was a salesperson's daughter and nobody crossed her.

Given so many people have quit, I just think it's a toxic environment all around and that's just stuff that doesn't change, unless they fire EVERYONE and the management is replaced completely. That is a rare event. I don't mean to be negative but I've worked at placed like that in my life and really, it's just so hard work in a place like that. I like Aronia's advice on how to try to at least get a clear picture on expectations and how to address the jerks.

If this environment is condoned,
It is a poor reflection on the manager.

Funny y'all should say this... My manager just pulled me into her office and told me she sent a girl home for yelling at me.

Awesome!!!

Yes!

If you decide to keep working there, results go a long way. If your lead qualifications are higher in either quantity or quality, you'll get noticed and rewarded.

And if you are not rewarded for results, the you probably don't want to be there.

I think Aronia gave great advise and I'm glad that the girl was sent home for yelling... Not cool at all!....xo

It might not be possible to maintain "professional and courteous relationships with co-workers", since they're being quite unprofessional and discourteous to you by yelling at you. Yell back. Anger is the only thing people like that understand. And yes, do go over their heads and complain to management.