If the copying creates consumer confusion about the source of goods and services, then yes, a trademark gives you the legal grounds to act against the infringement.
But consumer confusion depends entirely on the nature of the copying. For example, posting similar content on social media would not be considered as sufficient grounds, while a competitor changing their logo or brand name to mimic or impersonate your brand is exactly the kind of situation that a trademark will help you resolve.
Even if the current copying does not meet that threshold, registering a trademark is advisable to prevent infringement by other parties in the future. A registered trademark would, for example, allow you to send a cease and desist letter requiring a competitor to stop using infringing elements.