GP's are really poor at picking up deficiences like Vitamin B and Vitamin D, I think they get extra money for handing out anti depressants. My son spent 18 months going back and forth to the GP, brain fog, fatigue, leg pain, by the end he was sleeping 22 hours a day, they desperately tried to get him on anti depressants but he refused, eventually he had a locum instead of one of the normal GPs that checked his vitamin d levels and he had none. 8 weeks of massive dosing and he was fine, sadly he had already had to leave University by then so he got a lovely £9k debt for nothing thanks to his GPs complete incompetence.