I’m so lost

It’s like being spoken to in a language you simply don’t understand at first - combination of shock, fear and denial. Utterly ‘normal’ and completely confusing. Particularly with young children in the picture. It can help to take a friend or unflappable relative with you for discussions with your medical team, someone who can remember or write down what is said but also ask questions on your behalf if required. Others on this site will have some good advice about telling your children and letting them know, in appropriate ways, what’s going on. Chemo isn’t fun but for many it’s doable and not as bad as they had feared. Important thing is to feel confident about your medical team and the advice they are giving - to feel that way, you need to be able to talk to them about your feelings and your questions. It does get easier as you have a clear plan about treatment. Hard as it is to see the good side,  your bc has been found and it can be treated. This is a good place to ask questions (none are silly) and to let your feelings out safely. Best wishes.