Something's kicking my butt today

Last night I was out by 9PM. Woke up around 7AM. Took Leah to Ballet at 11:00AM and came back home. Had lunch and passed out on the couch! This is so not me. I never take mid day naps and Saturdays are always busy for me with errands, shopping trips and laundry and I always have energy. It's 4:37PM and I just dragged myself out of bed and I have a terrible heartburn, so bad that the first thing I did when coming downstairs was to gulp down two glasses of milk. I planned to go to World Market today to get a few things and I can't even get myself to get in the car and drive. I'd better be pregnant! How else would you explain all of this??