I ended up in intensive care, 8/10/11

     On wednesday the 10th I was bicycling around Albany Park delivering sandwiches for Jimmy Johns.  At around 1:30pm, I was struck down.  I have no memory of what happened.  The last thing I remember is riding east on lawrence between kedzie and kimball and waving to a friend of mine.  A witness called an ambulance and I was rushed to St. Vincent's in Evanston.  I woke up a day later.  I had a severe concussion and a head wound down to the skull, but very luckily not a skull fracture.  I have to take anti-seizure medication and am forced to stay off the bike for at least 6 months.  If anyone has any information as to how I was struck down it I would be eternally grateful. There are some odd clues though.  There's no damage to the bike.  I ride a single speed origin 8 frame with a weinmann 18dp wheelset.  The last time I had a minor fall I at least knocked the headset off.  but nope- all components are in perfect working order. The fingerless gloves I wear are completely covered in blood, like I protected myself or at least tried to.  Again, any information would be helpful.  Also, I'm now in the market for an adult tricycle if anyone knows of one for sale somewhere.