Hi 63 Hottie,
Welcome to Healing Well! You're definitely in the right place. I've never heard of any problems switching from one PPI to another. Many people are switched from brand to brand while they look for one that works for them. I personally wouldn't hesitate to use the one you have until you get the mail order brand.
Could you call your doctor and ask this question? The other really great resource you could use is your pharmacist. I often call or stop in to ask the pharmacist questions like this one.
Here is a very good resource you might find helpful:www.aboutgerd.org/site/about-gerd/treatment/medication-faqs