Ok I created a web called "sharepointstest.com", well that didn't work out well so I removed it from central administration and created a new one called "test.mydomain.com" and that is working and I was able to create some site collections.
Now here is the problem. When I'm in one of my test.mydomain.com/sites/blog and when I click on any of the tabs on the top of the page, such as Newsfeed, onedrive, sites it loads a page that cannot be displayed and the URL is "sharepointest.com" which was the first site.
Not sure why it's linked to an old webapp or how to change this, any ideas?