Thoughts about death and fear of dying can be positive and it also can be negative.
If one is encouraged to obey Allah and is continuously reminded to stay away from sin, it is a positive thought. But if these thoughts make you depressed and they are a bit exaggerated to the extent that it is preventing you from performing your usual duties and behaving normally, then this is surely from Satan who is trying his best to make you depressed.
Therefore, ignore the negative feelings and focus on the positive thoughts. Look at the bright side of it and that Allah has given you another chance to take care of your family.
Death is inevitable as we will all die. It is only Allah who knows when and how. Therefore, we are on borrowed time and that is why we have to make the best of it in living our life to the fullest in a way that pleases Allah.
Supplicate to Allah to keep these feelings away and you will be alright with the grace of Allah in no time.
And Allah knows best