Illustrate This

so...
I look in my inbox today and I seem to have recieved an email xmas card from a mag I have previously worked for...featuring my artwork.

I did this piece for them a year ago. I was paid the very arbitary sum of £50. Re-use and copyright didn't even enter into it. I wouldn't have minded but I wasn't even asked!!!

Here's the rub, the lady who runs the mag has always been lovely and championed my work, so I don't want to piss her off by going mental about it, but i genuinely don't know how to make illustration work in favour of the illustrator anymore. I was 'hired' for a lucrative Tesco job two weeks ago, and then dropped to go in-house at the last minute after prelim sketches and Facebook joyous hype...I'm at the end of my tether.

If someone feels like giving me some advice I would just love anything right now that didnt make me feel like this is a complete mugs game

Help