White stick: should I use one or not?

So, I have migraines that often affect my vision greatly, my sight isn't the best to begin with (Example: If I were entering a grocery store and a little more than ten feet away is the huge sign that says "DELI", I can barely make out the words until I am at least four feet away from the sign), but I digress. I have considered getting a white stick, since my vision is getting worse and my migraines more frequent. The question: Is it okay for me to use a cane in public if my vision "shorts out" when I am in public? Or should I not because I am not visually impaired all the time? Many thanks.