One of the first signs of trouble in an organization is when there are financial or cashflow problems. If employees are not being paid in full or on time, there is reason to be concerned. Supplier' invoices that are more than sixty days overdue can also be a sign of difficulties within the organization. Many companies have strong product sales but, if they are not diligent in collecting the receivables of their clients, their line of credit or cash reserves are depleted.
A second sign that your employment might be at risk is if your employer approaches you about "changing the rules". This is often disguised as "restructuring". When you are told that the company plans to reduce your commission, change your territory or reassign you to another position, it may mean that they need to make changes to improve the company (operational concerns) or that they may be trying to get rid of you. I have known people who were "politely fired" when their commission structure was changed, others who were moved into unattractive job descriptions (while the employer either hoped they would resign or replaced them with an inexperienced relative and still others who were told that their hours would be reduced to the point that they couldn't support themselves and their families with the income.
The third reason that an employee should be concerned is if s/he is abused in any way. Physical, sexual, or mental abuse are not acceptable at any time. Sometimes employees are ignored or neglected as "punishment" if they have not agreed with the employer and this ostracizing can not only be devastating but can also be copied by co-workers so that the employee feels shunned by everyone.
If you feel that you are experiencing any of the above in your career, it is important that you are able to talk with someone who can support you and help you to decide the best course of action. Do not make a hasty decision but do consider what you might have as options.
Communication with the employer may help to resolve the situation for you. You may want to ask a union representative or mediator to help with this. Abuse needs to be confronted and not tolerated any further. If it persists, you will need to report it, so you and others are spared further problems.
Of course, it is always a good idea to be improving your skills and networking so that if you decide to change jobs you are able to do so easily.
No matter what your situation is, you need to focus on your work responsibilities and provide your employer with the work s/he deserves until