So going into the soul cairn I told Serana to soul trap me instead of turning me into a VL, but now that im finished, where is the soul gem with my soul in it? i've been looking for about 45 minutes, and i bet its been looking me in the face the whole time... So any helpful imput would be greatly appreciated.

Do some Soul searching...

cwutididthar? lol

It should be in one of the chests underneath one of the huge Black Soul gems that drain your life. Eat a Soul Husk to kill the life drain, btw.

Make sure you have the quest thread to get it back. I had no problem the first time through, but the second time through did not get the thread quest and could not get it back.

Does it happen to have a unique name? I happened to find a Reaper Gem Fragment under one of those, but i'm not sure if thats it.

No unique name that I know of. It's just randomly in one of them.

are you a ginger jk

Ended up finding the quest thread in the misc section of the jounal. Quest markers help so much when the npc's don't give the slightest clue were to even start looking.
Thanks for the advice guys.

You're welcome.

*flies out the window very super-man like*