Hi Nat
It must be so frustrating. I think it is worth a long chat with your oncologist to discuss your concerns.
I had a close experience with a friend being diagnosed with BC when her first child was 3 months old - she didn't think she would fall pregnant again naturally (she was over 40) and she did and had a gorgeous little boy. Unfortunately when he was 6weeks old she was diagnosed with secondary cancer and she passed away when just after he turned one. I know this is horrible story but it is true and I just think that it is worth talking about all of the risks and benefits of the treatments.
I friend of my Mum's was diagnosed in her 20's and has gone on to have a beautiful little girl. I don't know the details of her cancer or treatment but she did chemo and I think she may have harvested eggs beforehand too. I am not sure if her pregnancy was via fertility treatment.
I am lucky to have completed my family before being diagnosed but 5 years seems like a hell of a long time to wait to try for something you really want. There seems to be a lot of research out there - maybe things have changed in the past few years and they can modify your treatment or give you some alternatives.
By the sound of that baby board Sarah mentions - hopefully it won't be too long for you.
Amanda xx