Swim bladder problems--please help!

Hey all,
I just noticed today that my young female betta, Nessarose, seems to have a bad case of swim bladder disorder. I've been suspecting it for quite some time but just today she's begun to float over on her side and is incapable of swimming to the bottom of her tank anymore. She stays on her side at the top, tending towards the corners.

I just haven't ever experienced this before, and I really need to know what to do. If there even is anything I can do. So please let me know ASAP.

Thanks.

Well, first of all, I have to apologize. I don't check my water parameters--I know I should, and I have no excuses. However, I do have another betta in a tank with the same water, and he is perfectly fine, so I assume that the water is okay.

The tank is a 1 gallon. It has been set up for about a month. I feed the betta two Hikari pellets every day--she's still quite young, and small. There are no other fish in the tank. I change the water once or twice a week (it varies), 100% changes.

Like I said, I'm using the same water and changing just as often for my male betta in a different tank. This little girlie has acted sickly ever since I got her.

Okay, an update.

Some hours later, now, the girlie seems to be able to swim -much- better, and is not floating on her side any more... but she is now VERY swollen! What could be the problem? I figure it's either:

a.) swim bladder (but since she's swimming better now, I don't know if this is it any more),
b.) constipation (and I fed her a pea just in case), or
c.) eggbound.

Does anybody have any ideas? Thoughts? Anything? She acts normal now except for being swollen... oh, and her scales are not pineconing so I ruled out dropsy.

She is a very small betta--when she grows more, I will upgrade. And in any case, I would appreciate thoughts on making her better, rather than just non-constructive criticism.

Anyway, her swelling seems to be subsiding. Perhaps it was just constipation after all. She does seem to be doing better.

She's actually much better now--the pea worked.