@Janine *****
, are you on the original entry stamp from the VISA itself or are you on an extension of stay? If you're on an extension I have seen people denied exiting thailand because they didn't cancel their extension, but that was at a land border, not when flying out.
If you're on an extension of stay I'd take the paper from the uni, go to the immigration office and cancel your extension. If you're not leaving the country that day you should also get the 7 day stamp to exit the country at that time.