You relax by doing the things that people on this forum do which successfully manages anxiety. Read the personal success stories section on this site you will see:
TEA Forms (Thinking Error Analysis) read here
. People who do these daily report to dramatically decrease worry and anxiety. It really works for me. If you do the forms you will see that everything you posted falls under classic thinking errors.
Meditation and deep breathing
Walking, stretching and other exercise.
Learn and practice a belief system: Buddhism, Christianity, etc.
ACT (Acceptance and Commitment Therapy) - I use this and it really helps.
Medication and /or herbs/teas - I take Holy Basil
If you do nothing and just keep Googling you will continue to suffer needlessly. Notice that you have been Googling for 10 years and yet you are still fine, except for some basic classic anxiety symptoms. So you need to put in some effort to straighten out your thinking and body chemistry.
I hope that helps and that you get some relief : )