Help! I've just written the climax and can't get back down!

So here is my dilemma. I have reached the climax of my story, the big fight between the main character and the nemesis has played out. The hero almost die but I am stuck. I want to wrap things up but don't really know how to do that.

Now that I have reached the fight the story was leading up to for so long, it feels like my brain is shutting off. Like the creative cool aid has run out. Like all the writers blocks in the world have teamed up and formed a wall between me and the last chapters of my book. Quite frankly all the wind had seeped out of my sails, leaving me stranded in the middle of an ocean.

Any tips on how to get this ship back on course?

It depends how many chapters are left and whether you want to write a sequal. If you want a really captivating ending, why don't you do something where the character killed off. If you have other characters with them, a few other chapters after could be their reactions(if written in 3rd person ) Just a suggestion

Godlypopo, thanks for the suggestion. I hadn't thought of that. I may give it a go.

You could also show the effects of the battle on other characters aside from the hero and nemesis. Even if the hero's fate is a bit up in the air, following how other characters deal with the aftermath can give the story a sense of closure.

It also depends on what type of ending you want.

Happy? Bittersweet? Pyrrhic (won but at a great cost to the point it's not really "won")? Downer?

Knowing what type of ending flows naturally from the climax, along with the type of ending you want (they might not be the same, but you should be satisfied with the ending regardless), might help you figure out how to tie it all up.