Other than being grossed out, I seriously doubt that you have been harmed significantly. First of all, I doubt that your spirulina absorbed enough of anything to harm you - think of the difference in size of a human and a mouse and what the mouse likely actually consumed versus what may have escaped in gaseous form and been absorbed by the spirulina. Secondly, if you check the ingredients of your mouse poison you will likely find that the active ingredient is Wayfarin, aka coumadin - which is commonly prescribed as a blood thinner for humans.
The muscle pain might be from tension you feel over the whole incident.
Certainly cleansing and doing the things you mention are a good idea and you might want to get yourself some vitamin K2 to help offset any blood thinning effects (that is what the vets prescribe to prevent/stop intestinal bleeding when dogs eat a bunch of mouse killer), but unless you begin having serious problems, which I highly, highly doubt, I wouldn't worry about it.