For your nose: use a neti pot, or even just a measuring cup with salty water. Pour through nose (you can find all kinds of stuff online regarding details of technique). Do this a few times a day.
For your ears: buy an eyedropper-style bottle and fill it with rubbing alcohol. Every time you swim, immediately tip your head to one side, put in some drops, then tip your head back over and let it run out. Repeat on the other side. Because of the structure of my ears, I used to get water stuck in there all the time, but this works like a charm. I even do it after showers.
Have you considered aqua jogging instead of swimming laps? I get sick easily and I find that keeping my head out of the water is much better for my health. Aqua jogging without a float belt is a VERY good workout.