EllieFrog

Don't worry, you're fine. The same thing happened to me when I first started taking bc pills. My first period on OTC Lo was super long. It seemed to drag on forever and I was getting concerned as well, but eventually 10 days later it finally stopped. My periods after that were much lighter (between 3-5 days long) and much more regular.
That happens frequently and it will work out over time. The first few periods may be messed up, but it will get back on track.

Don't think about switching yet when you've just started. It will take your body at least a few months to adjust to the new hormones and whatnot.
As for the mood swings, that happened to me as well. It got pretty bad at certain points where I would laugh one minute, cry the next, and then sometimes I'd turn into a raging b (everyone noticed which was the worst part). It's common though. If the mood swings persist after 6 months (or so) on your current bc, then I would consider switching. But for now it's way too early to tell. Just give it time.