I am so sorry to hear of your loss, and the way you are feeling right now.
Your children are wrong, you know, not you. Your love for and relationship with your husband were, and are, two completely different things to your love and relationship to your children.
You do not mention whether your huband's death was very recent, if so I would say not wanting, or rather not being able to do anything but weep sounds very, very normal to me.
You know, perhaps you should make an appointment with your GP.
You ar a woman of faith, so please do turn to those who share your particular faith. A certain consolation can, in my experience be found that way.
After bereavements, while I am still at the stage of just wanting to weep, and the following stage where the slightest thing makes me cry, I have found it helpful to resort to setting myself a goal and promising myself a reward.
For instance, I shall go for a twenty minute walk, and while I am out I WILL NOT CRY. If I am succesful, I will have one small square of chocolate when I come home. You can substitute any other activity for the walk and set a shorter time limit too. It may sound childish, but it has helped me, so I hope it may help you.
Don't worry about putting on weight - you probably aren't eating properly right now, are you?
If not, please consider that eating one good meal a day, or two if you can manage it, might make it easier to cope emotionally.
I shall pray that you are given the strength you need to tackle this appallingly hard part of your life.
PM me if you think it would help.