However, I've heard that servers used to make a killing a few years back. Now, not so much. For example, today I worked from 1030 to 1600 and came home with only $43. And I had to tip out from that. That also doesn't include the taxes they will take out. Soooo, on a day like today the dishwasher will make more than me. Unfortunately, the past few weeks have been really awful like this.
I can't say I'm surprised. Lunch shifts are always hit or miss, especially Mon-Thurs. And if you were there til 4, then I assume you were one of the closing servers. That also takes your per hour rate down, if you've got a dead period in the middle of the day.
I still stand by what I said. A server working some amount of dinner shifts at a reasonably busy restaurant (especially those who ONLY work dinner shifts) is going to average, per hour, far more than most of the back of the house. I say this figuring that many of them are really only there for maybe 4 hours before being cut (say, starting at 5, and being cut at 9). Some time for sidework, and you're gone.
Even your example- you came home with 43 bucks for a 5 1/2 hour shift. That's a little over 8 bucks an hour, not including the 2.13 you make hourly (unless it's more- some places pay slightly higher than that for working a lunch shift). $8.50 per hour taken home (so, after taxes) is actually about the same or better than my take home pay from one of my jobs back in the US. I'm not saying it's rolling in luxury, but I stand by my statement that it's about average for that type of job. Hell, if you had two more tables, you would have cleared my take home pay from my accounts receivable job.

The nice thing about waiting tables (and honestly, I LOVED the job, and would have kept doing it for much longer than I did, if I hadn't needed back surgery) is that if you're busy and working hard, you're typically rewarded at the end of the night with a very good amount of money. At other jobs, you can run your butt off and at the end of your shift, you're still pulling 9.50/hr before taxes, no extra.
Of course, what's hitting you most is the economy (obvious statement is obvious. haha). A lot of people aren't going out to eat as much as they used to. It's tough, but it's tough for everyone. I tip appropriately in the US (18% or so) but honestly, as you say, I just prefer the UK system so much more.