1. In your settings, you can set the page you land on when you log in (Projects, My Work, etc.)
2. Check your URL you are using to log in. You can save any URL in Workfront, and then when you log in, you'll go to that page. The basic login page is https://[yourdoman].attask-ondemand.com
I second what Greg said, check your bookmarked page - you might have bookmarked the project itself. I've recently supported a user who had the same issue and that's the first thing that popped into my mind, it's bookmarked to a page they've looked at previously.