Trying to Sleuth Out how this happened: Part one.

I am sure you're asking what does it matter how it happened? Well, frankly because I don't want to make it any worse and if I have a hint how it happened, maybe I can avoid it.

Potential #1

Occurred as a result of a Tetanus Shot (and cat bite) I had in February 2018. 

Why this seems like a possibility.

• Prior to June of 2018 my White Blood Count (WBC) was consistent and normal at around 6.0. And I have a long history to refer to thanks to a medical monitoring diet plan that did CBCs frequently. 
• I always have a bad reaction to a Tetanus Shot. For two days afterwards I have a relatively high fever and feel very bad. This February 2018 was no different. I actually scheduled it on a Friday so I wouldn't need to take time off.  To me this indicates a strong immune reaction. 
• January 2018, my WBC came back at 6.0 so I know that it was normal then. I had the shot in late February.
• June of 2018, it dropped to 5.5... and has steadily gone down since. 

Why this seems unlikely.

• A reduction in WBCs is associated with menopause due to a reduction in reproductive hormones. I had an FSH test (generally a test to tell you if your body is asking for more sex hormones) in August 2017. It was a tiny.. 3.0. And up to that time it was always lower than 7.  But in January 2018 I had an FSH test and, for the first time, it was up around 45. It has never been close to under 20 since that time. IMHO showing that I truly started the process of lowering hormones in Winter of 2018. 
• I have a theory that after you stop bleeding your RBCs increase and perhaps there is "less room" for WBCs in the blood flow and they naturally reduce. 
• My WBC has gone down, but, it is still normal. 

Conclusion: The WBC reduction is a natural change seen in menopause due to less reproductive hormones.  The reduction coincided with indications of menopause and is likely not related to MGUS.