constant battle

I have recently have been rather ill with common colds and other germy things.
It has been a constant battle trying to keep my bloods under the mid 20's and I feel just constantly drained from it.
I want to know if anyone has any tips what helps them keep their bloods normal when being ill.

Any help will be much appreciated

I did all that as I have just finished the PASTIE course which is the DAFNE course
But even that wasn't helping much. I just kept getting one bug after another, was pretty ill for around a month and a half.
Was just wondering if anyone might of had any other techniques which might of helped them