I know it can feel overwhelming at first especially of the unknown , one day at a time really works for me . My treatment is also Herceptin but with taxotere /cytoxan . I started Herceptin first had it 5 times before chemo and I still jogged 3 miles a day up to my chemo only felt a little winded but otherwise good , so if that helps to understand its ok then with the chemo I've had 2 out of 6 so far , the first was NOT good , also i recomend getting a port i waited till before my second chemo treatment and i suffered but after it was placed much better i had it placed right where my bra strap is so i can still wear tank tops . The second time of chemo much better and I'm walking 2 miles a day . So whatever helps u feel good , I say do it .. Try to have a normal life as possible , take this as a bump in the road it's not the end !