Hi,
Your job sounds like a warehouse & admin & customer service job I had, back in France. In order to meet the deadlines and avoid being sacked (in France, there's much more unemployement than here) I had to work a minimum of 10 hours unpaid overtime a week, up to a maximum of 35 hours (unpaid overtime)! And we didn't have bonuses or annual salary reviews.
I lasted 5 years and a half and was eventually sacked (but they had to pay me 2 months indemnity because they didn't have a valid motive, + 2 months notice). I was one of the oldest employees (at just 31...). Basically, the motto of the owners of the business was: 'squeeze the orange, and then throw away the skin'.
I would advise you to look for a job elsewhere. Possibly in another industry. That's what I did. I had only ended up doing a job like that because I couldn't find anything better at the time, anyway.
Good luck.