Firstly my condolences on the loss of your husband.
I am only new to this forum and have just read your post. I have not lost my partner but in the past two years I have lost 2 parents and a son, so I understand focusing on others to make sure that are okay - especially your children and losing track of what is happening around you.
Unfortunatly no-one knows what you are going through unless they have gone through such a great loss themselves and they don't understand why you have not recovered as fast as they think you should.
You never recover from losing someone you love so much and you will always love and miss them and this is okay. Your friends may never know what you are going through and be greatful for them that they don't, you wouldn't want a friend to go through what you have been through, even if you wish they could understand a bit more than they do. The best you can do at the moment, if you haven't already, is try to get a foothold in life. This could be finding a support group with people that are going through the same thing as you, making time at least once a week for an hour or two and catch up with a friend or find a hobby or sport that you have to go out to be part of. This may not be an easy thing to do but kids always learn and draw strength from their mum, no matter what age. Show them how to continue without their dad. You have made it this far, so it seems to me like you have the strength to take the next step, just take a deep breath and remember it's not about moving on, just continuing to live.