I agree with what Brian is saying. It is very common for young girls to have irregular periods, usually simply due to hormonal fluctuations that tend not to stabilize until well into the 20's.

As for Guillain-Barre syndrome, many vaccines can rarely cause this, and it is more common with multiple vaccinations at one time. It is advised to give Gardasil on its own to lower the chance of this happening. The flu vaccine by-the-by, is a prime offender for Guillan-Barre.....and its protection is known to last only 6 months....