Convict Cichlid

It is possibly a problem.

Look down on her from above - do her scales stick out like a pine cone?

If they do, she has dropsy. This is a symptom of several diseases rather than a disease itself, and the sticking out scales occur when the kidneys fail and the fish can't remove water from its body. The underlying disease could be bacterial (potentially curable) or viral (impossible to treat).
Some people claim to cure dropsy by using epsom salt baths (ie make up a tub of epsom salts and put the fish in that, don't add epsom salts to the tank) or by using eSHa 2000. However in most cases it is incurable and by the time the kidneys fail enough to produce dropsy there is nothing that can be done to save the fish, I'm afraid.

If the scales don't stick out, there might be something you can do. Bacterial infections can cause swelling, which has an effect on the swim bladder which causes swimming problems. These are more difficult to treat in the UK as we don't have access to over the counter antibiotics; the medications we can get aren't nearly as strong as antibiotics. Look for Interpet anti internal bacteria or eSHa 2000. If you are not in the UK, see what antibiotic your fish shop recommends.
And overeating has been known to cause swelling and swimming problems. In this case, fast the fish to see if there's an improvement. If you don't have a quarantine tank, you'll have to fast the whole tank for a few days, which isn't a bad thing to do.

I'm sorry to hear that.

You do have a choice. You could try epsom salt baths and/or eSHa 2000 to try and save her. Or if she looks to be suffering, put her to sleep.