Psychology problem in trading

I have a problem. It is that I have a week or a day when I understand everything perfectly well in the market and my trading and analysis are good, and I earn money, but literally the next day everything goes not so well, or even badly, and this goes on for several days. I start to think longer, I trade poorly on Forex, although I analyze everything the same way (as it seems to me, the problem is not in the strategy, because it works well on backtests). This cycle repeats itself, and most of the time I either improve my trading strategy or change it. Has anyone had something similar, how did you solve it?