So very sorry @Canisha. It's utterly and totally shit. I lost my sister to this disease and I'm now raising her young kids. Try not to worry about your children. You've done your best to raise them well, and all that mothering that you put into them will always be with them. You will never be forgotten, thought of daily and spoken of always. When your girls have kids, how they raise them will be because of you.
If you're worried about how they'll get on without you, can you appoint a council of girfriends who can mentor and counsel them as needed? I'm not in your situation but I've mentally picked out a small handful of friends who could 'be there' for my children should I not be.
Do your best with each day you have. Make memories, and hug a lot. I'm so sorry. K xox