Hi Ro10,
I was diagnosed in early April this year, had lumpectomy and currently half way through 6 months of chemo (finished 4 cycles of AC, today just had the 1st cycle of peclitaxol), then radiotherapy for 5.5 weeks and hormone therapy. It is OK and normal to be terrified and yes, those people telling you "everything will be OK and stay positive" are actually not helpful at all, but they probably don't know what else to say. Just think that their heart is in the right places.
I have 2 girls aged 3 years and 11 months. So the most terrifying thing for me is not seeing my girls grow up. Yes there is a huge battle ahead but I tell myself think of the long term goal - being here to see my girls grow up - then any discomforts a long the way is worth it, truly. I thought I'd be really sad about loosing my hair, but when the time comes to cut it off (because I was just malting so much I was leaving a hair trail and I got fed up with it), I didn't even care! I bought a synthetic wig (from Wig Affair) but most days I'm just happy to wear beanie/badandas because it is comfortable and practical (the girls are so grabby). I know hair loss is temporary and mine has already started to grow back!
For me, to ease any worries or fears about your breast cancer, your medical team (breast surgeon, oncologist and radio oncologist) would be the best people to ask because they have the most intimate knowledge of YOUR breast cancer. For anything related to chemo, obviously the oncologist would be the one to go to. I found the chemo nurses are also excellent in knowing the side effects and how to manage them as they hear patients' feedback all the time while the patients are receiving chemo treatments. Everyone's reactions to the chemo drugs is different so just be mindful and aware of yours, and talk to your oncologist if you have any questions or concerns.