Resolution

In My Network Places, Disable and then Enable your connection to reset the count (alternatively, you can just restart your computer), and try to see if your send and receive increases dramatically. If it does, then you may have a few malicious programs running on your system.

Edit:
The number can also increase when you are downloading, or if XP downloaded a large number of security updates through Automatic Updates, however, I doubt it would increase that much within 3 hours. In fact, I doubt you could get numbers that high with 3 days of normal usage.