When people experience this during a cycle a lot of times it could be related to adrenal fatigue..
Also, there could be an in balance with the serotonin and dopamine levels, it doesn't necessarily mean dopamine levels could be low but rather dopamine receptors are non-responsive, downregulated so to speak.. everything stated above is merely speculation without blood work or knowing your history..
In the meantime you can incorporate DHEA (this may help with adrenal fatigue symptoms)..5-HTP (this can improve neuro secretions and improve your sense of well-being)..
In the meantime try to cut back on any caffeine, pre-workout or other major stimulants because this can down-regulate your dopamine receptors..
Take a few days off from the gym if need be and just unplug,during that time don't have any stimulants or anything and just give your body some adequate rest along with nutrients.. a system restart so to speak!
If the symptoms persist I would make it a priority to get blood work and also talk to your physician and maybe possibly go on some low dose antidepressant (Wellbutrin is a great drug with improving that feel good feeling along with sustained energy like effects).. it's not an overly aggressive drug that will put you on cloud nine at the same time affecting you sexually.. very low to moderate dosages can go a long way..