Poor Lulu, I'm so glad she's better
The symptoms sound very much like when Jeff ate magic mushrooms from his (very respectable, retired) sitters' garden, but that was Autumn
Saying that, according to this forum a wet spring can cause a flush in early May (see fourth post down):
http://www.shroomery.org/forums/showflat.php/Number/1383063 (please note, I Googled this out of curiosity, I'm not a regular member of the forum
)
Cornwall is a magnet for rich young things with expensive habits (especially on a warm BH weekend) - perhaps something was dropped which he snaffled
Jeff was bumping into things like he'd gone blind and had hugely dilated pupils, as well as panting, being unable to settle (walking round in circles) and tracking invisible flies - the vet referred to an eye specialist first appointment next morning, by which time he'd "come down" and was fine