Yup - sounds like a broody to me.
You basically have two choices - if you don't want any chicks then you need to stop her being broody. There are all sorts of methods for doing this - look up 'breaking a broody hen' on BYC and you will get some ideas (some seem more 'humane' than others to me.) However, you cannot guarantee that it will work - I have only broken a broody once, and was really pleased with myself, then a few weeks later she went broody again, and nothing I tried would stop her.
Your second choice is to let nature take its course, and let her raise some chicks. If you have a rooster then stick half a dozen eggs that were laid today under her and wait 21 days. If you don't have a rooster you can either source fertile eggs locally (buying them online and getting them shipped risks a lower hatch rate), or wait for a couple of weeks and buy some day old chicks from a local farm store to slip under her. The advantage of buying day old chicks is that they will probably have been vaccinated against some of the worst diseases. Also, you don't have to wait exactly 21 days in order to put chicks under a broody. Hens are not very good at counting - they will not be surprised at getting 6 chicks from sitting on 1 plastic egg, and they don't know when 21 days is up. You need to leave it at least 2 weeks from when she first went broody, so that her broody hormones are peaking and she will be receptive to the chicks. If you try to give her chicks earlier than that she will probably end up ignoring them, and you will have to hand rear them yourself, and give her more chicks in a week or so!
Whatever you do, don't just leave her to 'get over it'. As I said, hens can't count, so she won't simply get off the nest after 21 days if no chicks appear - some hens keep going for weeks and weeks. The problem with that is that a broody hen gets off the nest once a day to eat a bit and have a massive poop, but the food she eats isn't enough to keep her going for longer than a few weeks, and she risks getting malnourished and even starving herself to death if you let it go on for too long. (And the longer you leave it, the harder it will be to break her).
Good luck!