I'm 32 years old. I frequent the gym & train with weights. I use supplements(protein shakes, creatine, pre-workout) to enhance training & recovery. I did notice one stimulant based pre workout affected my libido & erection. I stopped usage of it & opted to use stimulant free pre-workout. I struggle with erection & ejaculate too soon. Never used to be like this. What tests should I go for &/or what should I avoid?