4 days but it was due to a horrendous stomach bug. The first 2 days I didn't leave bed and thought I was dying, the next 2 I was tentatively up and about but couldn't face food. For a while after it was little bits of very plain things as the thought of eating was still making me feel really ill. In total it was probably at least 10 days from the start of the bug to eating a "proper meal" again.
When I say thought I was dying I'm not even exaggerating - I collapsed in the hall on the way to the bathroom at one point and ended up badly dehydrated stuck in bed. It was when I was in a Uni shared house, I had to beg one of my housemates on MSN Messenger to go and get me a supply of electrolyte/sugary drinks and I think he saved my life
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