Losses

How do you overall deal with losses? I feel lost honestly... because I can be in a winning streak, and a single trade goes against me and I... just don't know. Imagine this scenario, I made 2% on average daily for 3 days but the next day I started losing 1% or 1,5%. I managed to cut those losses in half or even hit be. But I look at them and I think 'Wow this could be avoided', like it's a "stain" on the journey. I know it's part of trading but I wanted to hear something from the community so I can learn how to keep going without feeling beaten every time a red, a normal thing, happens.