Anybody ttc for over 3 years?

Jemma • TTC for over 3 years, confident my time will come in 2014 :)
Just wondered if anybody in the uk has been ttc for over 3 years like me (nearly 4) and that also already has children? I'm ttc my #3 I already have 2 daughters which were both conceived within 6 months! So was very confused and gutted when nearly 4 years has gone by and I'm still ttc!