Feel dreadful on a b12 loading dose- anyone else ?

[Mpark]

Hi everyone . I had my 2nd injection out of 6 for a b12 loading dose yesterday- I’m unsure if it’s a side effect or not but I feel so washed out , headache - generally feel crap - has anyone else experienced this during a loading dose of b12?
thanks in advance xx

I've been getting b12 injections for years and I always have a headache and feel a bit meh the first day or so after. I do find taking folic acid before the injection can help me feel less crap