Time line

I kind of wondered that myself. It seems off that there would be this many infected in such a short amount of time. The timeline seems off.

We're in the days just after Rick wakes up from his coma in the hospital, so yes, around the time of Season 1 of the Walking Dead.

I read somewhere that Rick's coma was supposed to be about six weeks.

If you watched one of the earlier web series of The Walking Dead you would have seen that Rick was potentially in a coma in that hospital significantly longer after the hospital went to *beep* and the world went to *beep*

One of the online web series showed two people a man and a woman who travelled to the hospital rick woke up in (made clear to us by the "Don't Open Dead Inside" sign on the door with chains and the bullet holes all on the walls). The two characters came across a woman in the hospital who had been there since the hospital was shot to pieces by the military and everyone left. She said she had been taking care of some patients and helping people who came by (which means she very likely took care of Rick while he was still in a coma and explains why he didn't die of dehydration as she would have been changing his drips).

So there is a good chance season 2 of FtWD may still be set earlier than when Rick woke up

(link to a wiki on the webisodes)

http://walkingdead.wikia.com/wiki/The_Walking_Dead_Webisodes:_The_Oath