Irregular period and need to surf?

Ok, once you read the title and you may think don't go. But my school says that I must surf even if my period is due. This is my first year of periods and yesterday I had little bit of blood on my panties. And today I got a pad but there is not much on it. I have had this happened before and sometimes I would have blood on my panties and the next few days I didn't have periods. I have camp in a few days and my school has new wetsuits and they say that you won't get wet much. What do I do? Should I surf with my period because I don't know when it's gonna come again because now it is on and off. My friends in the other classes surfed even on their period. And I am not going to use a tampon