Omo! It happens, you know. Sometimes I have no energy for anything. Dunno if it is the hormons, the fatigue, the stress or just some depressed moment but I have learned to accept that those days I won't do what I should or want and just deal with it the next days in order to not add stress. That way I'm not blaming or pressuring myself and I feel better. It is normal to have up and downs. Sometimes I go for a walk, read a book, listen to music to have some stimuli and sometimes I just sleep to regain energy for later.
It will go better don't worry.