Wow. That sounds a lot like me. I'm so sorry. I don't know your situation, but in mine, a few of the people I try to care for do actually fully accept my limitations, and if anything want me to stop trying to protect them, so they they can protect me. Maybe that's similar for you. Now, there are other people who truly do just try to keep taxing me without giving much back. But there are a few, a couple, who want me to be comfortable resting on them while I need them. If that's where you are in any relationship, I urge you to let yourself relax with those people. And well, if it's not, then it urge you to take time for yourself as much as possible. PC can help.
You are not worthless. You can't see that now, but you are not worthless.