Did you take them regularly, or just here and there? If you took them close to every day, you need to be slowly tapered off by your doctor. Do NOT get your guidance from GNC.
If you only took them here and there (not every day), you should have little to no withdrawal. You will probably experience some rebound anxiety either way.
Do this correctly, with the help of your doctor. I think you're going to be just fine. Let us know!