gastric flu twice in four weeks? thought this couldnt happen

[Bexybear]

Am in despair as me and DS have horrible puking bug again four weeks after the first bout. Symptoms seem identicle but i though if you had something once your body developed imunity to it...Anyone know about these things? Could it be something else, should i see the GP? help!

It will probably be a different one despite identical symptoms. DD had puking bug every other week near enough last winter when she started nursery.

I have just got a cough after having about 3/4 days free from the last one. Also might be that your immune system is low from last one leaving you vulnerable to this one. Thats what the doctor said when DS got tonsilitis on top of a cough that he hadn't full recovered from.