First, if I were in your shoes, I would not do anything until I talked to a Massachusetts employment law attorney.     Many offer free consultations.  However, even if you have to pay for an hour of her time, it will be well worth it, because she can tell you if you are protected and advise you on how you should proceed with the reporting of the illegal activity and with your on the job behavior.  Depending on what, exactly, you are planning to report, there are several Massachusetts statutes that may be relevant.  Massachusetts General Laws Chapter 149, Section 185 protects public employees who report, or refuse to participate in, any activity or practice that the employee reasonably believes to be in violation of a law, rule, or regulation (or which the employee reasonably believes to pose a risk to public health or safety).

Massachusetts General Laws Chapter 149, Section 187 protects health care workers who refuse to participate or oppose a practice that they reasonably believe to pose a threat to public health.  There is also state and federal law that protects individuals who report fraud against the government.

These laws also provide for the recovery of damages, including compensation for lost wages and litigation costs. This answer is an extremely brief explanation of the various laws and considerations that may come into play with a retaliation case.  So, again, contact an attorney.  Good luck.