When I have losing days, they are huge, always larger than what I can make because often times when I reach 6-7 points per contract, I am done for the day. I don't advise others to trade as I do as I average down on every signal, yes, have done all the back/forward testing and 4-5 years of real time trading, the numbers are there based on my style that are positive, but on losing days, it will bother me a bit, I will double check to see if I did anything wrong, am sure most traders would do the same. But fully aware this is a numbers game and usually in 3-4 weeks or less, made up the loss.
You get to certain point where you just expect to be profitable each day and that's it, you know that losing days will happen, and not risking anywhere near betting the farm. But I think we all want to think we should never have losing days.
Great deal of study and work, now more study though than work, but in early years, if I wasn't stubborn and persevere, I'd never made it, it is like in your blood, but my age now, I could never do that again. This was the hardest activity in my life to overcome, all the mental issues to deal into, learning to program, working nights somewhere else and yet always on my mind.