I am on my 3rd virus in a row, literally 2 days feeling ok in between. 1st two were colds - this seems to have gone straight on my chest. Also getting over root canal infection and an ear infection that followed one of the colds. ABs for tooth gave me thrush. The second cold was worst for years, knackered for 2 weeks by it, couldnt work the first week. Any suggestions on boosting immunity very gratfully received!