My links on the top have disappeared

Our website USED to have a list of about five links on the top of the page, including “Parts & Fittings”, “Contact us” etc…. and now suddenly, they are gone. The webdesigner who was doing some work for us and creating a new website for us had access to this website and I don’t know what she’s done to make these headings disappear (she no longer works for us). They were just links with words that when you clicked on them, they took you to other parts of our website, but now nobody can see that we even have a “Contact us” page etc. Anyone – help help please! I have spent over two hours trying to figure out what she did or how to make them show up again – but no luck ??
we’re DESPERATE
Thank you!!!