the devil loves it when we do this which is why He puts this self doubt in our heads...this is why it's important to love yourself as you are & be thankful to God for another day on this earth to help someone else. Spending time each day with Jesus really does help. Pray, give it to Him & He will take care of it.
But then it breaks your heart to realise you can't make it better. All of a sudden you see them for the hurt person they are and suddenly you just want to hug all the pain away. But, sadly they are trapped in their own misery.