I really understand...I was the same way for many months. your feelings are normal--but for your husband's sake and your child's sake, you have to get past this phase and move forward. it is not easy as you think about losing your love and the father of your child, but you have time now to spend with them and make it the best that it can be. as a cals, you have so much on your plate with little ones and working and the stress and worry of a progressing disease and what is going to happen next.
I suggest you talk with your doctor about anti-depressants or anxiety meds, and also find a therapist to talk with about your feeling. ALS is a family disease and you have to take care of your self also, because there is a lot on your shoulders right now and people are depending on you.
Some people are able to move forward out of sheer willpower, maybe that will be you, or maybe you have a strong family support group that can help you get through this initial period of shock. but I found that anti-depressants (a low dose) helped me control my emotions so I could sort them out and deal with them calmly. You are facing a crisis, and your whole world is being turned upside down. reach out for help. there is no shame in that.
Please stay in touch here. we care and we have all been there.