I was diagnosed with this last year. I had a lumpectomy , followed by chemotherapy and then radiotherapy  like you a major concern is that that is the end of the treatment as they can't offer other well known breast cancer pills . I finished treatment last  August and now am reliant on self examination , seeing the consultant and I have just had my first mammogram and that was clear. The worst thing is not knowing what to eat or how you can prevent it reoccurring  . I was terrified at first and even now every ache or pain I start to wonder. So my advice is keep going through with the treatment  , make sure you get a mammogram at the end of the year and if you learn anything about diet - let me know! All the best.....