If you can stay positive and upbeat that can help smooth your path through treatment. However don't beat yourself up if you can't. The pressure to be 'the good patient' is palpable at times, but often impossible to achieve for many of us.
A counsellor told me to "lean into the pain". I think she meant allow yourself to feel it because if you don't it can come back and bite you in the bum later. Avoidance can be problematic. So cry, howl at the moon, rage and vent when you need to, and you'll probably feel a lot better afterwards.
Cathartic, "providing psychological relief through the open expression of strong emotions; causing catharsis".
Having done that you'll probably be able to manifest some positivity afterwards! There's no right or wrong way to 'do' breast cancer. Feel what you need to feel at any given moment and don't beat yourself up about it.
And come here to vent any time! K xox