Hi There, I've Had The ADT (tetanus, Diphtheria) Vax Just

Hi there,
I've had the ADT (tetanus, diphtheria) vax just the other week. I needed to get the Boostrix (tetanus, diphtheria, pertussis) vax in order to start a new job however the doctor accidentally gave me ADT instead. I'm now considering getting the Boostrix however I've seen that it's not a great idea to get the boostrix if you've had a recent tetanus vax? The reason I'm concerned is that I've also just discovered that I'm pregnant and have been told I could have to get the Boostrix again in third trimester.