Welcome aBoard, er...gee, I guess calling you "half-wit" would be going a bit too far...

Anyway, I tried a thesaurus with the word shame; ignominy comes pretty close, but the word below seems closer. I know the word itself doesn't imply gratitude, but given a context similar to your example sentences, the gratitude might be implied/understood. I'm including everything that Gurunet gave me, because I thought it was interesting.
cha·grin (shə-grĭn')
n.
A keen feeling of mental unease, as of annoyance or embarrassment, caused by failure, disappointment, or a disconcerting event: To her chagrin, the party ended just as she arrived.

tr.v., -grined, -grin·ing, -grins.
To cause to feel chagrin; mortify or discomfit: He was chagrined at the poor sales of his book. See synonyms at embarrass.

[French, possibly from dialectal French chagraigner, to distress, become gloomy, from Old French graim, sorrowful, gloomy, of Germanic origin.]

WORD HISTORY The ultimate etymology of the word chagrin, which comes directly to us from French, is considered uncertain by many etymologists. At one time chagrin was thought to be the same word as shagreen, “a leather or skin with a rough surface,” derived from French chagrin. The reasoning was that in French the word for this rough material, which was used to smooth and polish things, was extended to the notion of troubles that fret and annoy a person. It was later decided, however, that the sense “rough leather” and the sense “sorrow” each belonged to a different French word chagrin. Other etymologists have offered an alternative explanation, suggesting that the French word chagrin, “sorrow,” is a loan translation of the German word Katzenjammer, “a hangover from drinking.” A loan translation is a type of borrowing from another language in which the elements of a foreign word, as in Katzen, “cats,” and Jammer, “distress, seediness,” are assumed to be translated literally by corresponding elements in another language, in this case, chat, “cat,” and grigner, “to grimace.” The actual etymology is less colorful, with the word probably going back to a Germanic word, *gramî, meaning “sorrow, trouble.” Chagrin is first recorded in English in 1656 in the now obsolete sense “anxiety, melancholy.”