If you are referring to the head drooping, that is normal, they are starting to make seed, you will see the inside of the head, sort of shedding small petals the head droops, the coating in the the inside fall off and the seed start to form. You need to feed it through out its life, until you harvest the heads. Simple blossom booster will work well. Miracle grow makes this but there are many brands. Once all the petals fall off and the lower leaves start to brown it is time to harvest your heads. Cut them off with enough stalk to be able to hang them to dry. Once dry the will easily fall from the blossom, and you can soak in salt and bake or harvest for your birds.
If you leave them on the stalk to dry with out cutting, you may loose your seeds to the wildlife.
If your leafs are what is drooping, this is caused by too much water, towards the end of the season the plant requires less water, the roots are actually slowing down. Pull back on the water and allow it to dry well in between.
I have these beautiful flowers all through out my garden. I am growing some to eat but most for the birds. Mine also have reached 12 feet and plus! are they just too awesome!
years and years in the dirt