Doesn't whipped cream usually go flat after a day or so, after you whip it?

As an experiment I decided to freeze a pint of heavy whipping cream I wasn't going to be able to use right off. I didn't know if it'd be ok after freezing or not. But I whipped it up on Sunday night (it looked weird pouring out of the contain, but it whipped just fine) and its still whipped today. No sign of it deflating at all.

I don't know if I stumbled onto something here, or whether this is normal. I seem to remember it starts to dissolve again in about 24 hours.