when I did cd before i always used to keep a tetra in the freezer and then if i was out for the day I would take one with me and it would always be nice and cold, also another good way to eat it was to get it out an hour or so before I wanted it, let it melt a bit and then open the packet and eat it with a spoon, like an ice cream, lovely!! and it lasts for ages!
tetras were also great for grabbing first thing in the morning and popping in my bag, as I very rarely have time in the morning to make up a shake before school run!!
Good luck with it all, I am starting back again on 1 june!
x x