What performance issues/symptoms can a pilot expect while taking off above MTOW?
Firstly, you did goof up by not checking what the refueler did. Your life depends on that fuel, and in light aircraft the gauges are notoriously unreliable. We've probably all done it but we shouldn't - always check!

However going off your figures you might have been what, 20 pounds overweight? That shouldn't cause such a massive decrease in performance. MTOW isn't an on/off switch. It's a point that has been selected as the maximum allowable limit - with a safety margin built in. You should never exceed MTOW even by a bit, but if you do you will (hopefully) live to see your kids birthday thanks to that margin.  

I've flown a C172 right at MTOW (actually about 5kg under but close enough). Acceleration is slow, meaning you use more runway. Rotation actually feels normal thanks to ground effect, but once you leave that you notice a degraded climb performance. If you're over MTOW these effects are the same but amplified. If you are very overweight, you will climb in ground effect but will struggle to go much higher than 20-30ft. 

As for your flight though, it could have been affected by a tailwind or high temperature/low atmospheric pressure. What was the temperature like on the second leg? Vy will theoretically get you the best climb rate even above MTOW so it doesn't make sense that you could climb below but not at that speed. Maybe there was something localised affecting the ASI, or, if I may be so bold, your technique on the day wasn't 100% :)