Rhesus D Blood Group

Hi all

Found out I am d negative blood yesterday after a ectopic pregnancy.

I've been given the Anti D jab for future pregnancies but just wondering how long I'm covered for? I had a miscarriage before this ectopic too really don't want it to happen again but also not ready to rush into trying again as I'm obviously emotionally hurt.

Has anyone had experience of this? I know it is very rare! Thank you. Xx