Well, if you can discard a medical problem (hormone levels, diabetes, arteriosclerosis.. Or something else) seems a mental issue to me, I have experience some “problems” like that under a very high levels of stress.. Libido is also dependant of serotonin levels in your system, I hadn’t been “overtrained” in PE.. But notice a better ejaculatory control since the beginning of training.
Also the Spring season can be helpful enough .. In México we have the expression “como burro en primavera” means that after the winter the spring sun make you go as hard as a donkey all season
Try a weekend on the beach with your girlfriend or wife (or both) ;) if you experience that problems even there.. Run to see a doctor