I am not here to diagnose you
you may or may not be catastrophizing. To be honest, such a cognitive behaviour is quiet common among people with ASD due to the almost always present anxiety disorders, especially, GAD, which symptoms include catastrophizing.
People with ASD also are well known to find the unpredictable nature of life, extremely unsettling and stressful.
Due to other common traits of the ASD brain, we generally operate experiencing more stress than normal,
which reduces our capacity to experience stress in every day life.
In order to reduce our risk to being exposed to too much stress, we as ASD people generally like to create and follow routines rigidly so as to limit the amount of stress we are exposed to, keeping our stress loads within our known limit.
Such routines means that everything is predicted, and kept within our limits. We know we can cope under these conditions / circumstances and environments. We keep stress to a level that we can cope with as we are controlling what we are experiencing and know we can cope with what we choose to experience.
Problems arise when we experience the unknown, basically, because we don't know what we are going to experience if the experience is unknown to us. And due to trauma experienced in other circumstances that we know we can not cope with, we start to worry, in case the unknown may be one of these experiences.... unknown perhaps even including death...
Meditation, relaxation therapy.
Meds for OCD sometimes are also prescribed for people with GAD.
Some antidepressants are prescribed, including older tricyclic ones. I personally recommend Clomipromine.
Although regular GPs MDs wont prescribe this old gen med, psychiatrists should be able to though.
If you can find one that understands ASD that is....
Hope that helps.