A Dodgy B12 Injection?

 

I have a B12 injection every three months.

After my May injection, I suffered all sorts of heart fluctuations, shortage of breath etc. I talked about them on-line and it was suggested I have thyroid function checked and that the other symptoms were down to a shortage of B12.

Since my August injection, everything has calmed down and I haven’t had a heart fluctuation.

I just wonder what went wrong with the May B12 injection.