If this is your first time being hijacked there will be a higher chance of getting your items returned to you.
Always double-check the link before you click on it, and never never sign into anything unless you see the green https lock next to the link in your address bar (and even then just check it again just in case). This applies to every site with sensitive information, not just Steam.
in case you have no idea what i'm talking about:
That's in Chrome but there are similar things in other browsers.