There's a 'My Watch List' submenu link under the 'Marketplace' tab in your account.
There is also a 'Marketplace' tab on our main site which could be causing the confusion. If you are logged in, but out on our main site, hover over the top-left corner of the page where it says 'Hello ___', when the options appear, click 'Your Account'. This will bring you back into your account where you will find the correct 'Marketplace' tab.