The biggest thing we have to fear in the apocalypse is the loss of the internet.
It means that people will have to stop gaming and reading social media. Instead of getting wound up and being made anxious by stories on the internet about how we are all going to die of cancer caused by eating too many Cadbury's cream eggs we will have some proper stuff to worry about. The most difficult thing of all is you might have to have a conversation with someone and will either have to be really nice to them or be prepared to kill them in cold blood.
On the plus side, we'll all successfully manage to lose weight and keep it off. Without petrol or electricity for your cars (unless you can find a friendly person with solar and a charging point) you'll get fitter from all the walking and hunting you'll have to do. No one will complain about cats shitting in their gardens again. There maybe a problem with feral dogs temporarily, until they all get barbequed. No one will complain about Asbo neighbours. Instead you'll be actively recruiting them to head of security for you local milita.
Terrorists will find a place in society again as their skills in blowing up shit, can be put to good use breaking into food warehouses. Frustration with shitty managers who do fuck all will end over night as they find themselves surplus to requirements. If your MIL doesn't live in the same town going no contact instantly becomes easier. If shes a right one she'll have a reputation and be higher up on the hit list due to her lack of social skills. Failing that, there are no longer repercussions for murder and if we reach the stage of cannibalism, it simply makes decision making much easier.
Anyone with any sense will stockpile copious amounts of alcohol and chocolate and hot sauce. You will need hard currency after all. It will likely solve issues with global warming by reducing those emissions drastically overnight. You won't care so much about wearing the latest trends - second will become all the rage. You won't be jealous of people who live in mansions because it's easier to keep warm in a small home. You won't worry about your kids getting fined for not being in school in term time or failing maths anymore. You'll be pleased they took up hockey rather than football as the stick doubles as a weapon. And you can burn that fucking violin.
In answer to your question, yes you are letting anxiety rule your life too much. In some ways if the worst should happen, life will become different and less stressful in certain areas with no time to worry about much more than simply surviving.