Originally Posted by
Kipling
you probably moved the seat too much so that you are putting pressure on the prenial (sp?) artery. keep the seat level, and if the problem repeats i'd look into getting a better saddle, one with a prenial groove (not entirley sure on the spelling or pronounciation of the artery, but its the one that runs between your legs and modern seats have a groove or hole to avoid putting pressure on it)
i imagine it will just be a passing thing, if it persists as coolkingler1 said - go see a doctor.