How long has she been going for? I've found that my kids have gotten sick for the first few months then it seems to slow down. It was especially bad this winter though I would say stick with it but it depends on how much you are paying (and wasting). The other thing to think about is that she may well start giving things to the newe bubby when she comes. DD2 has been getting colds since she was 2 weeks old - but I guess you have to expect that sort of thing with older siblings.