Am I the world's biggest chump? Am I gathering Karma point? (Am I just plain stupid is an option too.)

I'm booked off for a long over due vacation from June 21 - July 05. [approved over two months ago]
My 'meme' T.A. requested July 02 off and got it. [last week]

The Administrator who approved 'meme' T.A.'s request now says; 'but there has to be someone here to babysit be there for the students. [We can't have them sitting around shoving their thumbs up their arses unsupervised can we -( that's my input)

'meme' T.A. 'CAN'T cancel her week-end plans now'. 'Has to absolutely go on this trip'.
I booked my return to Vancouver for June 30th so I could have July 01 to July 04 to myself to get back into things.

Here's where me 'the stupid chump' steps in:

I agreed to go back to work on July 02 instead of the July 05 as first planned.

I can't stand my job and I turn around and do this! What the hell is wrong with me?!?

*sigh* I'll spend July 02 updating my resume I think.