You didn't let anyone down. What we deal with is a struggle and you are lucky your family and friends are being understanding. If they don't tell you otherwise, don't speculate that you have let them down. You don't need self inflicted guilt. You mentioned other things are bothering you as well, do not let this get you down even more. Even though you fell like you are at rock bottom, every experience you have, you learn from it. Try to see the good in it, maybe you should just volunteer instead until you are ready for more responsibility. Don't let this scare you off from living life. You ARE worth it and you deserve to go to college if you want to and to try to work again, none of it is easy. You took the step and got a job, you can do it again. Good luck, be strong.