Context:
In 2007...
A family friend died of breast cancer. My 80yo grandfather had three heart attacks, but (barely) pulled through. My mother has been diagnosed with late stage liver failure. I was diagnosed with degenerative disc disease in my lower back.

Onset:
I think those facts are contributing to my anxiety but the attacks didn't start until after I suffered Fentanyl withdrawal. The fentanyl withdrawal was painful and demoralizing. I lost total control of my mind and body and experienced deep, deep depression and pain. That was three months ago though.

Symptoms:
Now, at least once a day out of nowhere I start feeling dread. Then the feelng of dread turns into thoughts of my own mortality or my loved ones mortality. My thoughts turn to the future being bleak and inevitably being filled with death and pain. I try to push it out of my head but the feeling of dread stays for usually about an hour, constantly reminding me of those negative thoughts and this makes me feel like I'm going crazy. Sometimes it makes me wonder if I have a brain tumor or something that is causing this, but I think this is probably just irrational thinking. In short, I just have no control of this and it is loss of control that is the worst feeling. I don't like to go to work or out of the house during these episodes because I don't want anyone to see me.

Info:
I am taking clonazepam to sleep (.5mg) and I am confused as to whether this is helpful medication to have, or whether it is contributing to the problem. Any advice regarding medication or strategies for coping with this would be much appreciated. I am very naive about anxiety disorders, since I've never had them on this scale before. I have a gut feeling that this is PTSD caused by the Fentanyl withdrawal, but I don't know what to do about it.