General TDEE help.

I was using this - http://iifym.com/tdee-calculator/
So I am 34, Female, I weigh about 140 pounds and I'm about 5'4- 5'5
I work 12 hours a day doing very hard physical labor. If I use Mifflin-St Jeor it says Physical Job PLUS daily exercise... but I don't do daily exercise on days I work. Nothing worth mentioning anyway.

How do I calculate my TDEE now? I maybe work out 30 minutes 2 times a week now plus a very on my feet job.