I no longer use MDMA but when I was doing so the only thing I found got worse for me was the the difficulty in peeing.
It got to do the point where it would take me like 2 hours to pee!! (sorry if thats too graphic)
that, along with the loss of magic eventually caused me to stop using it but I wouldnt say that the hangovers got worse, in fact I wouldnt say I ever really got hangovers from it per se, I guess I was one of the lucky ones!
bhut yes! you should definately test your pills - ez test and dancesafe kits are the most widely available ones.
However, there is one research chemical vendor which posts videos of their chemicals reacting with the regeants similar to the way in which mdma would, so I guess testing them may still make them appear as containing mdma even if they do not.