Ok I Was Told I Had A Vitamin D Deficiency

ok I was told i had a vitamin d deficiency and put on 50000 u of vit. d after taking the first tablet on Sun. I started to experience a severe headache and dizziness. Had the headache til Tues. and a was extremely tired couldn't keep my eyes opened called my pcp and she said it couldn't have been to much for my system. Felt pretty good this morning and now around 3 pm I the dizziness had started back with mild head ache coming back. Could this still be from that tablet ??