Feeling run down and catching everything often comes back to how well supported your everyday defenses are. When your body is carrying a lot of everyday wear, that support has less to work with, and you feel it as being slower to bounce back than you used to be.

It isn't about being weak or just getting older. Your defenses are doing their job every single day in the background, but that build-up inside quietly drags on them over time, which is why you end up catching whatever is going around and taking longer to feel yourself again afterwards.

The good news is your defenses can be given more to work with. Ease that everyday wear and support them properly, and your body tends to hold up far better day to day. There's a simple, natural way to go after exactly that, and most people start to notice its effects over the following weeks, feeling more resilient and not getting knocked down as easily.
Based on everything you've told us, here's what we'd point you to.