Someone who has gotten the flu recently probably had H1N1. It's a highly infectious bugger. As is typical with pandemic strains, it tends to squeeze out any of the other seasonal flu strains.

There was that experiment with ferrets reported the other day. Interesting results. One result was that ferrets co-infected with H1N1 and a seasonal strain would only pass along the H1N1 infection to other ferrets. So, not only do pandemic strains out compete other strains by being more infectious, they seem to also block other strains from getting passed along.

Well, the bigger bit of news from that same experiment was that there was no evidence of any co-mingling of genetics info (aka mutating) within the ferrets co-infected with two different strains. That's where the various headlines about "No evidence of superbug" came from recently.

That said, it's always hit or miss to know whether you've had the flu since many other bugs can produce similar symptoms. But it was probably H1N1.