Marketing is driving the software?
They don't care about security?
System administration is outsourced?
Quit. Leave now. Take only your jacket. Your adrenals will thank you later.
The sensible option is to learn to relax. By informing your boss, you've done your job.
If you really want to make an effort then you can make a weekly report called "Security status bulletin" listing/naming the worst problems plus their possible consequences. Send it to the people who need to know.
Keep evidence, make sure other people know you repeatedly told the boss, collect your wage packet, go home every day. If you think this is unprofessional you need to Read more Dilbert.