jesgardner - By my reckoning you should have your 2nd jag by this Friday 30th April. That would make it exactly 12 weeks.
I don't know which part of the UK you live in but if I were you I would be contacting your Health Board or whoever is responsible for sending out the appointments in your area.
We are using the "letter in a blue envelope" system here in Scotland for most appointments but there have been cases where the letters have gone astray and appointments missed. Not many I hasten to add.
Hope you hear soon,
Dorrie