This is basically The Walking Dead meets John Dies at the End. Not that that's necessarily a bad thing. I do think, though, that this story would need some more uniqueness to stand out from the myriad of zombie stories out there (good and mediocre alike). Zombies can be a great literary "tool", but cheapily ripping off every other such story that's already been made is not the way to go about writing anything. Not that I believe you would ever cheapily rip off anything.
So how about this: guy takes drugs. Wakes up in Zombie apocalypse. Gets guns and blows away zombies to escape city. Authorities chase. Catch him. Turns out the drugs made him think people were zombies but he was killing innocent normal people.
I'd up your time period to about 50 years. Pollution, global warming, overpopulation, and economic collapse have turned America into a shit hole. Your teen, Brian, wants to go on ignoring the harsh reality his generation must face, so he turns to a common drug being handed out by the government as an "aid" to "societal adjustment disorder." Everyone else is on similar drugs for similar "disorders." At some point in your novel your character collapses and wakes up in a hospital where he finds out he has been infected with a virus that is slowly eating away at his life. Worse, a growing percentage of the population has it also. There are riots in the street, rogue policemen, etc. People are dying. Some people, like this father, a low government official, are trying to ignore the disease and go on living normal life. His father insists Brian is fine, and that the pandemic is a political scare. Others are rebelling, and some are even trying to flee, despite impending quarantine. There are also rumors that the government is trying to exterminate unimportant parts of the U.S population, and that the cure to the pandemic is locked away in a government lab. Worse, Brian can't stop taking his drug. He can't get a straight answer whether it is the cause of his disease or a potential band aid, but his withdrawal prevents him from taking any action at all. Brian must struggle against widespread misinformation, deniers, crazed police, rebels, and even the government, as he jumps from cause to cause in an attempt to save his life, which will ultimately lead to his exodus, as he crosses the border into Mexico (and or Canada) just as he collapses for a final time into death. Your novel will explore themes such as, the vapid American culture, the fall of the American empire, addiction, narcissism and denial, lost values and self identity. Brian ultimately escapes the U.S, which is symbolic of his spiritual transcendence from our exaggerated materialistic society, which is fast approaching ruin.
