There is no shame in wearing a mask to put a barrier between you and the germs. Carrying a small device with a HEPA filter to clean the air is a good option too.
There are other hygiene measures, like washing your hands more regularly than normal but especially when coming into the house, not touching eyes, nose, or mouth (basically your face) as those are the principle routes of infection. Finally, boost your immune systems by making sure you have a good diet, and supplementing with plenty of vitamin D3, some K2, zinc, and quercetin. In winter our supplies get low due to lack of sunshine. I take much more than the recommended dose, but find out about these compounds first, and check with your GP beforehand if you are not happy. Asking for a test is good to see what your current levels are.