Again, you're not telling your employer anything he/she doesn't already know.
It's not that what you're saying is necessarily wrong. There's a very good possibility you are doing the work of multiple people, seeing that layoffs were rampant when the economy tanked and hiring has only recently picked back up again. But what you're forgetting is you aren't the only one who has been impacted, as your co-workers are likely in the same boat -- both the overburdened ones still at the company and the ones who lost their jobs.
Highlighting your accomplishments and hard work without coming across as whiny means you'll have a much better chance of a few extra bucks in your paycheck.