Has anyone experienced the following? I wonder if this is normal or if I should consult my doctor...

I have been taking Metformin for about 4 months now (about 3x/day for PCOS per my doctor's instructions). I do my best to not eat a lot of sugar unless it's in the form of natural sugar, like fruits for example. But yesterday, I slipped and had a slice and a half of apple pie. Immediately afterwards, I felt sick to my stomach and became EXTREMELY tired! So tired in fact that I had to lay down and didn't get up until about 4 hours later!

Is this a normal reaction when taking Metformin and eating large amounts of sugar? I'm a little worried. Is it "lactic acidosis" or something else? Thanks for your help!