My kid asked why I was crying

6yo walked in on me in the garage yesterday while I was having what I'd call a breakdown. Nothing specific happened, just a wave of everything hitting at once. He asked if I was okay and I almost lied but... I just told him "Dad's sad today." He sat with me for like 10 minutes and didn't say much. My partner found us and helped me inside. I'm sharing this because I used to think I had to hide this stuff from my kids, but maybe they deserve to see that their dad is human too.