Oh well, I can't take it anymore, just wanted someone to support my decision or give me advice now

Here's the situation:
Background:
I am currently an active member in my school's Aikido Interest Group (Aikido IG), as I am a senior now and due to my knowledge in handling administration matters, the former committee members passed me a vice-secretary post recently.
Problem:
Everyone thinks that I am slacking around when I wasn't given a single decent post to do. Apparently, the newcomers do not know me at all till now despite numerous chances of my name and position being mentioned and neither am I able to know each and everyone of them in order to facilitate with future administrative works, especially attendance taking. I tried helping the secretary recently and what she gave me was actually some ridiculous work! Taking the attendance of the newcomers when some of them had already went home and I do not know them at all and neither do the rest of the newcomers know them. I don't whether is it called bullying in this case, but I was treated as transparent whenever I am not need! I don't know what to do now, leave the damned committee and be a normal member or just put up with it?
* The secretary was kind of cramped up with too many newcomers and monetary issues, that's why I wanted to help her since people had already notified me of the situation. And I believe that another pair of hands sure facilitates the process and allows everyone to go home earlier. >.<
Thanks in advance!