Telling yourself could have done "more" to help a situation, is sometimes a lie.
Sure, sometimes we could have put forth a little more effort, but if you were giving so much that you were constantly drained and stressed, you could not have given more to the situation without injuring yourself.
You did everything you could while still surviving. You are not a bad person because you didn't sacrifice yourself completely for something/someone else.
You did everything you could.