Metformin???

How many have been put on Metformin? I started with the 500mg on Thursday. It has given me the worse kind of stomach cramps, unbearable diarrhea, and fatigue possible. I have to go up to 1000mg on Thursday of this week. Then 1500mg the next Thursday. I can't imagine having to take higher doses of this stuff. I'm miserable. I've lost 5 pounds in 3 days. Gatorade and crackers are the only things that go down. HELP!!!!