exhausted

i am so tired and sad.  I have given up sugar entirely since I found my energy nose-dives whenever I eat sugar.  I am running a 1/2 marathon on sunday - and I am so concerned that I won't have the energy to finish.  I am up in the middle of the night (not like me)... and I don't know what to do.  My husband just looks at me with a blank stare.  He has depression issues... and I just can't be everyone's rock sometimes.  

I have hypothyroidism, diagnosed after 3 surgeries and lots of hormones for Asherman's Syndrome.  3 amazing children, the oldest being very sensitive and lately moody.  She needs so much support and extra attention from me.  I give it freely, but it is wearing on me.  My 2nd child is joy joy joy, and only crabby it seems when tired.  My 3rd is a boy (3) and he sends my head spinning since he is always on the run - usually with a smile on his face.  Laughing non-stop.  He does wear me out a bit, but oh is he dear.

I feel so odd and exhausted.  I also have a lot of back and neck pain lately... and I think I am constipated.  I have been eating a lot of fiber and ezekial sprouted bread (so good)... but things areh't working...  

Help!