I used to have severe panic attacks thinking i was going to die in a fiery car crash in the rain regularly. Friend in Cali suggested I try a non-addictive anti-seizure anti-anxiety medicine called Buspar. After about 2 weeks my panic attacks were completely eliminated. What a Godsend. Other than psychosis panic attacks are some of the worst I have been through mentally in my 30 year mental illness journey. Good luck keep a stiff upper lip it can get better. It has for many of us here who decided to come back and help others through their suffering. Be patient with your self and mind. It is mostly just a chemical imbalance in your brain. Finding the right chemicals to correct it personally is the tough part. What works for me may make you worse or vice versa.
Take care
Also when you are going down the rabbit hole with those negative thoughts try to catch yourself and replace them with something positive like one of my favorites "I have an abundance of health, wealth and happiness. The hard part is noticing that you have been thinking negatively in the first place cause sometimes thinking that way can seem so natural to us.