Enough?

Words of comfort. I have really good times when I can do extra things or expend energy when absolutely needed, and then struggle with guilt and sadness when I crash and burn so easily after doing so, missing things like church and dance class and not driving myself and other important events. How do I explain when I have a good window and then turn around and be totally down. I worry every day about all the things I am not doing, about knowing I need to really push through something or to get through an event knowing I will fail completely at something else after that because 

I have overdone what my body will allow right now. Huge life events coming up in the next several weeks.... Totally scared that my best will not be enough because my best is so little most of the time these days..... Hopefully I can listen and live these precious words of a beloved prophet. Always a work in progress, some days easier than others.....