Hey Amanda,
Hang in there, you can do it, don't let any one convince you of anything else.
Check and see if you can get a mentor to help you. Check with a local high school that works with adults or check with a local community college. Listen Amanda, you are special, there are things that you can do that others without add can't do. We can't allow ourselves to fall into a victim mentality, our attitude or mind-set is 98% of the battle. I believe that we can all have successful lives; we just need to work on having a healthy self esteem and have a realistic view of what success is. We are in charge of our own feelings, so it is up to us to tell ourselves over and over if need be that we can and will do what we set our mind on to do and then do it. Reward yourself when you make progress. Don't fall into the trap of negative thinking. Amanda, fight that hopeless feeling, don't let it win, take stock in what you can do and then maximize your effort towards what you are good at.
Blessings, Tom