The main reason is that your domain is new, has no history and no links pointing to it, while github.io is much older, features a huge amount of content and has an enormous number of links pointing to it.
The best thing to do is use the canonical HTML tag to explain to search engines that both feature the same content, but drmaak.com is the primary source. (See Google's article - Use canonical URLs)
It's impossible to answer why search engines aren't displaying your results - there are hundreds of possible causes. To start with, you need to consider what keywords you are searching with.
If you want to take this area more seriously, you should register your site with Google's Search Console and Bing's Webmaster Tools.