Doing the Work but Not Getting Payed or Any Credit

I am a private school teacher of a quite small institution. And you maybe  guessing it right away, we're quite understaff. And because we lack people to work on a project, as a teacher we are asked to lend some help for some. 

As an ICT Teacher, I've been marked as part of called Research and Development Team, but basically it's just a team for marketing and promoting the school. Letting the school be known to others.

It's quite a lot of task because the first projects are to create some brochures templates, tarpaulins, video plus a deadline not a strict one but of course put some pressure on the back.  

And then questions came to my mind.

Will I still do this work if I am not getting paid or won't get any credit from my works?

Why does it feels like it is embarrassing to accept this job? Like "Pinapagod mo lamang sarili mo hindi ka naman bayad dyan. G na G ka pa."

Why do I think that other people would look at me like,
"Why are you so crazy about that"
"Why are you  so passionate doing that?"

I once read that if you're in this point it's more likely you're doing the right thing. I guess?

The main thing is, why would I still be concerned?

If I look back, The situation that I have right now, this is exactly what I wished for.

To have an opportunity to work with more knowledgeable people, be able to improve my skills, apply art, learn, teach.

After all I feel fulfilled.