Is it possible to OD on Tums?

There are lots of weird (read "annoying") things about being pregnant.  The ever present indigestion (now including heartburn!) is one of them.  I think that I probably bring some of it on myself because I often end up lying down after eating but my stomach is constantly indigested (not that I know if that's a real word).  I checked with the pharmacist and she said that it was ok to use Tums while pregnant but perhaps I should have clarified that I meant using 4 extra strength Tums per day...