Teamwork?

So apparently we are a team - although I seem to be the main one taking up the slack on other people's projects. I know that when someone's new they can't be expected to hit the ground running but it's beginning to take the piss. Every time we get a new list for data entry for the big project my boss tells me to split it between the whole team (6 people) but she, the new guy and her best buddy don't seem to get round to doing theirs but because I actually care about our project I end up doing it. I finally flipped today so one of the other members has been trying to help pick up the slack. The annoying thing is I'm not even considered to be a member of that project team so they'll take the credit and I do the work - grrrrrrrrrrrr