You can only take it day by day, worrying and stressing yourself out won't change anything either way, right??

You're aware of a possibility of a spread but give it time to heal from the sprain first. It may take weeks if it was a bad sprain.

I don't know if RSD shows up so soon after an injury - or if you have it already does it spread that fast - that is a good question for the pros here.
best of luck - give the sprain time to heal

sprain info links-
http://faqs.org/health/Sick-V2/Fract...d-Strains.html
http://familydoctor.org/online/famdo...uries/010.html