Hello, well I've just had my fourth bout of sickness in as many months and am getting pretty fed up of picking up every bug going around.

Does anyone have any suggestions about ways of boosting your immune system, such as supplements or anything?

Sounds like you need a good rest from training.

Well your occupation is something to consider.
As a teacher, you're exposed to every bug that is going about.
I'd have thought your imune system was probably pretty good as a result.
I've had a problem with viral neuritis recently and I do find that taking a multivitamin supplement helps with that.
As always, first port of call should be your GP.
Downside to them, generally I find, is that they focus on the symptoms and not the cause.
Hope you feel better soon.

I agree with mule - see a GP!
They do indeed focus on symptoms, but that is the way Evidence Based Medicine works.
On a more practical note of things you can do - rest, eat a balanced diet and lay off alcohol etc.
Gentle exercise can boost the immune system, but heavy exercise if you are already nackered can be a bad move.

You good eat your bodyweight in echinacea supplements, but from what i've read there is sod all evidence to support the fact it's good for the immune system.