Battery issue, is this normal.

I realize the warranty on Lenovo batteries is 1 year. I have a 3 year warranty on the laptop but it doesn't include the battery. Now that that's out of the way here is the story. One day I closed the lid and the laptop didn't go to sleep like it was supposed to and the battery was drained completely dead. I recharged it and to my dismay had gone from 78% of original design capacity to 49%. So I had been living with about 1 hour of battery life.
Today I wake up to find a blinking orange battery light with this message in power manager: A battery error has occurred. The battery cannot be charged. Replace the battery.
So my question is, is it normal for the battery to just completely die? I was expecting an ever decreasing charge capacity until it just wouldn't last more than a minute ,but I went from 2 hours to 1 hour to nothing in 3 weeks.
The battery is a Sanyo, 9 cell. It says there have been 391 cycles. I realize the battery is a year and a half old, but I am disappointed a bit. Thoughts?

 

Does your battery fall under this recall?

 

Unfortunately it doesnt same issue as those listed, but with a different FRU and ASN. My batteries numbers are:
FRU P/N is: 42T4511
ASN P/N is: 92P1132