I know it can feel like such a useless sentiment, because feelings are different from reality, but remember that everyone on this message board sees worth in you, otherwise they would not be offering their encouragement and support. It's not completely up to you to decide your worth, you know? I see (at least part of) your worth from probably 1000 miles away. It's good that you post and keep in touch with people even when you're feeling so hopeless.
Try not to fixate on the score. Tests like that are not designed to be perfectly accurate for all users. And even if you see accuracy in that number, you can use your test results to try to get to the bottom of your problems, and use that number as a goal-setting device rather than a condemnation.
Feel better!