Could be some type of low blood sugar from training on an empty stomach. How long is it between training and the meal prior? I'd expect it to be a factor of your training and food timing.
Surge is essentially protein and sugar (that's way simplified), so there's no reason it should make you feel weird.
Also, are you using the proper serving size for your bodyweight? Make sure you're using the right number of scoops, and try adding even more water into it.
Are you new to using creatine or BCAAs?