2.1g of gabapentin is definitely going to make you a bit high, but its not really like MDMA. Personally, i prefer pregabalin (Lyrica) over gabapentin any day, but they do similar things. Either way, the high feels like being drunk and really excited. Not MDMA excited, but more like being really excited to see friends that you havent seen in a long time. Goes great with nicotine, but you might get a bit dizzy so watch out.
Oh and it will also make you crave the fuck out of sugary things, so watch out for that. And it makes sex feel amazing so either fuck someone of fuck yourself, either way youre gonna have an enjoyable time