Everyone should really know that there is always a risk in every step we make, so if you are losing today, try to stop it now and call it a day but never quit and come back again tomorrow. It is not always a bad day and it does happen once sometimes so don't take everything seriously because the odds might kill your funds for trading if you keep pushing your luck.
That is usually the thing. If you do not account for the fact that there is a risk in trading, how will you be able to manage the risk in the first place. Ask a lot of people today, they think every one that trades does not lose no matter how small, but how small you lose in a trade is dependent on your plan which includes how you were able to manage risks despite your predictions or speculations based on your strategy.
One major reason a lot of people will keep losing in trading till date, because they do not have that idea that trading is an educated gambling, and you need to have a plan and strategy to be able to make the best of it, otherwise you get screwed before you even realize it.