That's how the markdown parser works. It's not a bug, but part of the spec for markdown.
If you want to change how your posts are parsed, you can either write a new parser, or enable HTML in your markdown and type <br> for each new line break and for each space.
Thanks @pitaj . I am learning and it getting more interesting. I am able to do the menus also partially and with lil more time, I can i for the way i want i guess. Thanks you ur support.