A sad reality of 21st-century life is that most, if not all the websites of endeavours will have their websites hacked.  The realities of the spread of technology and the number of truly desperate people means that there are much more potential hackers.  You being small is no protection from that reality.  The more popular your website is and the more active you are on social media increases those chances.  This handy GoDaddy blog post provides some handy tips what you should do next.  GoDaddy is an internet service provider that provides internet security packages, but this is nonetheless a useful reference for prevention as well as your response.