How do you know for sure that you have anxiety?

Doesn't everyone?: But it's only a problem if you are substantially limited by your anxiety. If you're not sure you have it, then i suggest you not think about it much further (i.e., don't have anxiety about having anxiety!). Be active, engage life positively. If you're nervous a bit, that's pretty normal. Most importantly, do not hide from the world.

Look within: Anxiety is a feeling of internal angst and fear. As a general rule, it is good practice to develop the skill of recognizing one's internal emotionality. To confirm one's sense of anxiety & consult about treatment options, talk to ur family doctor or a mental health professional.