Be assured that you haven't 'blown it' in any way. I guess you should add a 0 or two behind 72 calories to really, really do that.
What we are
supposed to eat on a day is an average, which is anyway impossible to calculate precisely. For instance, when I eat an apple, do I need to substract calories because I don't eat the heart of the fruit, or is it already taken into account in the calories counters? No, seriously, we have to be strict when counting, but some things still and will always elude us, and we have to be aware of and ready for that.
72 calories overboard is nothing extrele to worry about, as long as you don't pile those extra calories over and over again every day for three months, that is, but I very much doubt it's in your plan. Maybe you'll exercise for ten more minutes tomorrow, and will burn those out. Or maybe you can have one less yoghurt and recreate the deficit again. What mainly counts is what you'll average over the week (we all understand it doesn't mean 20000 calories one day and nothing during the remaining 6, right
). If this is good, +/- 100 calories on a specific day won't make much of a difference.
So, you haven't blown anything. Those 72 (or 172, depending on how you see it) are nothing you can't 'make up for' later on.