Identify this poetic form

I am trying to figure out what kind of poetic form a poem I wrote is in. I do not want to post the poem here, but I will describe its form:

- It consists of 21 lines broken down into 7 stanzas with 3 lines per stanza (tercets).
- Each line has 6 syllables
- The rhyming scheme is: aab (for every stanza)

Thoughts appreciated, thank you.

I don't know, but maybe this will help:
http://www.shadowpoetry.com/resources/wip/types.html

If you wrote it in form, then it's probably going to be there. If you think it's a form, then maybe it's not. I think you should go back to where you got it from, like if it was from another poem, search the poem. If it's from a contest, look for the contest.