Yes, I think it's worth it to take the SAT with essay in October. Because you're still looking at schools, it would be a mistake to rule out anywhere just because your current SAT essay score is low (especially if you were able to beat your other SAT score goals). The pressure (and the tiredness) factors are real things to be aware of, but if you make a plan to devote at least part of your studying for the October SAT to preparing for the essay under real testing conditions, there's no reason why you can't improve your SAT essay score.
If you haven't already, I'd recommend checking out some of the great SAT essay resources on our blog, including our step-by-step guide to writing the SAT essay, how to get a perfect 8/8/8 on the SAT essay, SAT essay tips, 6 SAT essay examples you can use in every essay, and our analysis of the SAT essay rubric.