My advice: STOP. BEING. HARD. ON. YOURSELF.
Seriously.
Just keep practicing, with basic shapes first if you need to. Have patience with yourself. Learning new skills takes time. No one learns to read and write overnight, or even in a week or so; drawing is the same, if not more difficult.
You could also look into things to do to increase hand eye coordination, try different drawing techniques (maybe super quick pencil sketches, then go over it with pen), or buy some kids coloring books and tracing paper and practice tracing over the linework. Also watch how-to tutorials on youtube and try to follow along with them.
But mostly.. patience, don't give up, don't let yourself get discouraged, and try to keep a log sketchbook with dates so that later on (I mean months down the road, most likely), you can look back and encourage yourself with the progress, even if it's not a lot, it'll be something and should help motivate you to keep going and keep getting better. :)
