Thanks, everyone. It took about a day to recover...
I had eaten some falafel (a smaller amount) during a trip to New York a few weeks ago, and I can't recall any issues. Soooo...after having that falafel, I had a craving to eat it again on Sunday, and I got it from a Lebanese restaurant nearby. From the looks of it, they proabably used both fava beans and chickpeas, so definitely lots of fiber. At least my craving is gone! Don't know when I'll have the courage to eat them again!