What to do if I feel like I am in a hostile work environment?

A "hostile work environment" is one that prevents an employee from doing their work duties in a reasonable manner. Either by behavior or actions, a superior or co-worker creates an environment that is counterproductive to the employee performing their job. That having been said however, these behaviors must be "discriminatory" in nature and not just a result unprofessional behavior (i.e. rude remarks).

Note: Workplace discrimination is action taken against an employee because they are a member of what is known as a "protected class" (in other words race, religion, national origin, sexual orientation, gender, age, disability, etc. must not be a factor in their treatment).

Based on the limited facts that you have presented, it's not clear that neither plays a role in your situation. You should be aware that most employment relationships are what is known as "at will", which means that an employer can hire or fire someone for any reason or no reason whatsoever, as well has increase/decrease salary/hours, promote/demote, and generally impose requirements as they see fit. In turn, you can work for an employer, or not, your choice.

Note:  Exceptions to the above would be if there is a stated company policy covering your situation, or there is a union/employment agreement to the contrary, or (as stated above) if your situation has arisen due to some type of discrimination.

Unfortunately, the law does not prevent workplaces from being hostile, even excessively, unprofessionally, egregiously so. All that is barred is hostility directed towards a person due to certain specfically protected characteristics, the main ones of which are sex, race, age over 40, disability, and religion. (Some states also protect a few other categories, such as sexual orientation, national origin, and/or family status.) If the hostility is not directed at you on the basis of such a specifically protected category, it is legal.