What Causes Nausea After Routine Operation To Repair A Damaged Achilles Tendon?

A week ago last Friday I went into hospital for a routine operation to repair a damaged achilles tendon. Within 24 hours I had developed severe nausea, severe headaches and restricted and double vision in my right eye. I was confined to my bed for 4 days taking lttle or no food or fluids. My recovery has been slow. I have type 2 diabetes controlled by insulin. Prior to the operation I stopped taking warfarin producing an accepted INR of 1.2 for the operation. I also take digoxin, attenalol, losartin and simvastatin. I have now resumed my normal dose of warfarin and my INR was 2.0 in range last Thursday. Have I contracted this or another virus in the hospital.