Back to daycare and the yuckies

The boys have been back in daycare for about a month now.  They have had bronchitis and sinus infections/issues that won't go away or get better, each has had 2 rounds of pink eye, croup, hand foot and mouth, and other misc. virus issues.  We can't seem to get rid of the constant runny noses and coughs.  I really hope that soon they will build up some immunity to some of this.  Since once again we are on antibiotics and this is going to be our third round in a month.  This is why we pulled them out in the first place, I was really hoping that they were a little stronger immunity wise.  I'm not going to hold my breath since we are coming up on the cold and flu season.  It's just so darn frustrating!  UGH!