Hello, Sometimes I Feel Light Headed. It Happens Randomly. I

Hello, Sometimes I feel light headed. It happens randomly. I saw a physician a year ago and she thought that I maybe had anxiety. I didn't want to get on any medication and figured that if it's not a physical problem then I would just try to work through it. I am still having these sensations, maybe a few times a month. Enough to be concerned but not enough that it's disrupting my life. When this happens I do become anxious because I fear that I will pass out. How can I tell if this is anxiety or something else? At what point should I see another physical? thanks