Seasonal allergies medication side effects?

[Sekino]

My pollen allergies just kicked in badly for the last 4 days. I started taking Allegra D the second day because it was getting hard to work and sleep.

However, I have noticed that my stomach is acting weird: I feel this 'tightness', almost like that feeling you have when you get hiccups (except no hiccups)... It feels almost like my stomach has air in it and it is very uncomfortable. It seems like it started at the same time I started taking the meds (I don't usually feel that way). I did switch to Reactin this morning, just in case it was Allegra D; but my stomach still feels the same way.

Could the stomach problem be due to a common ingredient in allergy meds (maybe it's too acidic??), or is it just caused by the allergies themselves? I don't know, maybe because I have been sneezing and coughing so darn much, I messed it up or something.

If there's anyone who has experienced this, please help!