Hello! Welcome! I can understand how frustrating it is to have anxiety and not know why or what is causing it. I have anxiety with Premenstural dysphoric disorder. I was diagnosed about a year ago. I've probally had anxiety all my life, I've always been known to my friends and family as the 'worry wart.' About 3 to 4 yrs ago, I noticed my worrying was getting worse and it was not related to a stressful event that I could pin-point. I started seeing a therapist about a year ago, and through that realized I had alot of hidden hurt feelings and anxiety with my parent's divorce that happened 7 yrs ago. (When they first got divorced I was graduating from college, starting a new job/career, in the process of moving out;etc. so I had things to disctract me from dealing with their issues in a way.) I also started tracking when I would get the anxiety and noticed it increased greatly right before my menstural cycle. So I started researching, etc, and spoke to my doctors.
Journaling also has helped me alot.....helps me keep track of my feelings and work out my anxiety at times.
Hope some of this helps you!