I could have written your post. We've been sick since November - DDs (3 yrs, and 13 mos), Dh and myself. Earaches, HIGH fevers, congestion, etc. etc.
The doctors don't bat an eye and tell us it's 'normal' for families with kids these ages to get this sick. I sorta agree as DD just started preschool - the most exposure to lots of kids on a regular basis. My doc said it's a sign of building healthy immunity.
Given that, we dealt with numerous rounds of abx which resulted in a horrible weeping diaper thrush for DD2. Enough was enough, so I called me a naturopath and I'm working on strengthening family immunity to at least mitigate the effects of the viruses/infections, if not stop them altogether.
We've started: a dietary overhaul (MORE veggies, esp. green, more water, less refined, although we're pretty good to begin with..), multivite (Salus KinderVital), fish oil (Nutrasea) and Udo's Infant Blend probiotic every night. We all take it. We're airing out the house more, using a hepa filter, becoming more obsessed about hand and towel washing.
We can't live in a bubble and I accept some childhood illness will happen. Everywhere I go, my friends' kids or family members are sick and touching my kids...it's life. DH and I are sick of it but feel a little better that we're doing SOMETHING to support our immunity.
ETA Udo's Infant's probiotics taste 'sweet' in the powder form so I give the kids a bit on a teaspoon and they love it...initially in DD2's sippy but she never drank it all. Problem solved, though - try it...or in a teaspoon of water/BM/juice.
Good luck...you're not alone.