I'm not exactly sure what you mean by eye 'bugging'...normally I'd expect that to be a description of eyes protruding or perhaps opening widely. Kava has been known to make eye's cross or feel loose or wobbly, but that's typically a sign the kava or the dosage is properly strong or you've over indulged a bit. I consider eye effects to be a good sign.
Bloating and fullness, yes, a very common negative side-effect. Severity can fluctuate depending on the person, the volume, the preparation and the variety/strength of the kava consumed. Nausea can also be common, appetite suppression too, as well as uncoordinated wobbliness when the kava is particularly strong.
Next day sluggishness can also be a factor...but again, there are variables involved as to whether or not you'll get it, or how significant it will be.
For me, bloat, transient nausea, gas and next-day lethargy are probably my worst side-effects...especially since I can get all these negatives without necessarily having a significantly positive experience. I partially blame this on my genetics, 50 % at least.