I wanted to thank everyone for the thoughtful replies and suggestions. I will bring all this to my next doctor's appointment and see what she things.

Mark,
-this is what my psychologist originally thought, that it was a physical manifestation of anxiety/stress, which is pretty spot on.
-I get the jerking motion when I go to sleep as well. Some months I can joke that I'm getting a 6-pack due to the recurrent abdominal contractions. They are much worse at night or when I am trying to rest, take a nap in the afternoon, etc. Sometimes they occur when I exercise, particularly go for a run.
-My psychiatrist and neurologist never suggested any anti-seizure meds, I will be talking to someone about this.
-I drink things with caffeine daily, this has been normal to me for the past 7 years but the spasms only started a year ago.

Porkette,
-I do get a feeling when they are about to come on, like I can feel/see it in my head, a very familiar feeling. That's part of what bothers me so much about them, the fact that they feel familiar and "comforting" when they are happening, and how it messes with my emotions before/after.
-It's a good thing I don't care for diet sodas! I generally do not use sweeteners, this will be something I'll keep in mind.
-I do think they get worse around my period, I'm not sure I will need to write down times and details to see for sure.

Once again thanks for the warm welcome and concern, it feels wonderful to have people listening!