Dealing with PMS?

How do you deal with the headaches, backaches, cramps, and/or mood swings that are common for so many girls right before their periods?

Do you take any pain killers or try to isolate yourself when you're grouchy, or just ignore it and hope nobody else notices that you don't sound like yourself?

I do all the above, but it's hard when you have go into work at a job that require you to be smiling and friendly.