I put out a lot of energy into others, I get a sense of reward doing this. But why do I still feel like I’m not enough?

I understand how you feel.
Remember that one of the amazing people you should care for is yourself.
Be kind to yourself and do your absolute best to keep yourself in your best condition; that will influence the impact you have on others and on your overall contentment with life. Don't settle. Find what doesn't work for you and change it. Do that for everything that seems off in your life... until your life feels like your signature. Then, you will feel a deep sense of peace. I know I am speaking the truth, though I am still working on achieving that level of excellence (I am kind of inconsistent). Learn from me, be consistent and your efforts will bring faster results :)