I need help getting rid of these white spaces connected to the lines I'm drawing. Ive tried it with no fill but I cannot get rid of them. please help!
Select one of the line shapes and turn off the white fill.
That brush has a thickness independent of stroke. If you want to use brushes you can change the diameter of a calligraphic brush after double clicking the brush in the Brushes panel.
I'd just draw those lines again with the pen or line tool so the stroke works. When starting out regular lines (paths) are easier than brushes. Draw the lines, select the stroke again in the tool panel, with stroke selected you can control thickness and color.
If you want your stroke pointy you can select that under profile at the bottom of your stroke panel.