having issues with site address

two weeks ago i purchased my domain using dreamhost as well as the www.remarpro.com hosting package from them. i set up my www.remarpro.com account and it asked me to create a web address for the blog. i tried using the same name i wanted my site to be and the name i chose for my domain, but instead it told me the name was already in use and made me make the blog address blog.charliesbones.com…is there any way to change that? i thought my wordpress and my main site page, charliesbones.com would be the same thing?

can anyone help me with this?

thank you!