I'm going to drop out of a group project competition the day before the competition
Don't you feel you should be more responsible?
No, I think my group members can still manage it.
Backing out of the group project the day before the competition is irresponsible. Your group is counting on you to do your share of the work.
I always try to help my group as much as possible. Now I feel like I'm in a bind and I can't be a team player anymore.
If you know you have to drop out then you should let you group know. Even if you feel like you have no choice you still have to say something so that they can get a handle of things and don't fail the project. Just because you believe they can handle it doesn't mean they also don't have things going on in their lives.