Is she clenching any of her fins or her tail? If she is it could be a sign that she is close to dropping because mine tend to wobble and clench their fins and tail which shows me that she's having either what are called "Braxon Hicks" in humans,they're basically Practice Contractions, or real contractions, it depends how gravid she is at the time. If she's not fully gravid I know it's only Practice Contractions, but if she is fully gravid it's real contractions. Basically the wobbling is either a sign of being unbalanced from the weight, or she's going through either of the contractions. If she's really gravid and you don't see babies, it's most likely just the weight. If you see babies... Well you know what's happened.
Hope this helps!