Hi JD
I too question my existence, and have done more since my anxiety came about. My anxiety makes me feel detatched from the world sometimes, it's a weird feeling and horrible feeling, and I found that distraction is the key. Whether it be exercise, reading or watching the TV. The big question on why we're all here is probably the hardest to answer, and will on make me more anxious - so I try to ignore it. Have you tried lavender for when you go out shopping etc, put some on a tissue and inhale through your nose when your feeling anxious - it's a godsend!!!
Take Care
paniccomesandgoes(ish)