Don't blow it out of proportion - if you look at what you ate, there are no carbs and probably less than 150 calories so ultimately no real damage done - also don't be too hard on yourself as there is a danger of thinking "I haven't been 100% so therefore I've 'failed' and there is no point carrying on so I may as well eat everything in sight".
To be honest (and I'm not sanctioning this, it just worked for me), I used to have a slice of ham now and then as I needed something salty & savoury to contrast with my CD products as I lived on bars and choc shakes & mousses. It kept me on the straight and narrow is all I can say.