HR - it is possible that something etremely simple is at the bottom of this. Were you perhaps a little dehyrated and/or was it very hot in the supermarket? On the odd occasion when it has been freezing outside and I've been dressed for the weather, I have felt sick in the increased warmth inside but feel better once back outside in the cold. Look at all the simple things first and listen to Ginger, he knows what he is talking about and is more up to date with adult medicine and practice than I am.