Perhaps pumpkin seeds are not a "food" without the pumpkin and are somewhat
toxic.  A 2# plastic bag of raw seeds off the shelf is a long way from the
pumpkin patch and this excess certainly could cause gastric distress.
Perhaps it is like watermelon, we consume the seeds with the melon with no
negative effects.  Try consuming raw pumpkin seeds while you eat pumpkin.
Halloween is the 31st...very timely!

respectfully,

bruce