So sorry for your loss, and for your children’s loss. I understand your circumstances a little as my husband had mental health issues, and ended up taking his own life because of that. So I get the sectioning and being in hospital, and that in itself is so hard to deal with, let alone their death.
It always comes as a huge blow, unexpected and you are allowed to wear your rose tinted goggles and remember all the positives and the future dreams you would have had together. Your life as you knew it has gone and there’s no easy way around that.
This is a good site for chatting to people, and I am more than happy to listen if you need to get anything out. It is the worst time of your life and there’s nothing you can do except keep getting up each day and facing what needs to be faced, whilst trying to be there for your children as much as you can with your own grieving.