You're in a tough spot. As a practical matter, it is very difficult to bring a legal action against your current employer. While strictly speaking, they should not retaliate against you for bringing the legal complaint, you and I both know that chances are that they will. You can add the retaliation issue to your lawsuit, but meanwhile, you will be either in a very uncomfortable working environment, or out of a job altogether. It then becomes very difficult to find a new job, because when prospective employers find out you are suing your most recent employer, you get passed over.
Another problem is that there is a law against employers discriminating because of race, but there is no law against employers being unjust and downright mean spirited in general, so long as their attitude and conduct is not based on an illegal reason. So, you will need to prove that discrimination was because of race. Fortunately, the law assumes that few employers are going to openly disclose discriminatory intent, so there are various ways to show that the employer's stated reason for its conduct was pretext, and that race was a substantial factor in the employer's decision to behave as it did. Gathering evidence to show this can be difficult, particularly since your best witnesses will likely be your coworkers, and they tend to evaporate when things get serious.
That said, I would suggest two steps for you. First, it sounds as though you are doing quite a lot of work. You also don't sound like you would qualify to be an exempt employee. Are you getting paid for all the hours you are working? Are you getting paid time-and-a-half for all hours over 40 each week that you are working? If not, you may want to talk to HR about this, and if you get no results, talk to the Dept of Labor & Industries, or to an attorney. One or the other should be able to make clear to your employer the error of its ways on that score, if this is an issue, and since that it a simple matter of numbers, it is not very expensive or time consuming to prove. Retaliation could still be a risk, so you will have to determine whather to pursue this or not.
Second, I suggest you see an employment law attorney to discuss your case in detail. What your best strategy might be will depend a lot on the particulars of your employer, your own options, and the details of what has happened to you. Some of what you mention in your post has no bearing on your case, but by the same token, there may be many details that you did not realize are important that would help an attorney give you guidance. Many attorneys will do an initial consultation at no charge, spending 30 minutes or so getting the details from you and letting you know whether or not legal action is likely to be an effective option for your situation.