Your IP is your computer's or network router's address; are you at work or do you log in wirelessly or on someone else's network?

If no, call your service provider (the people you get on the Internet with, whoever you pay the money to) and tell them you have an IP conflict and they'll help you solve it; they assign your number when you get on the Internet. They can make sure your computer and they are happy with one another and each other's settings.

If you are on a network (more than just your computer), talk to your computer person (at work, in the library or whoever set up your wireless network) If you're using your neighbor's for "free" or one that is just "there" and they don't know about it; it's messing up who's on when because it knows about you even if its owner doesn't.