I've sprained my ankle and apparently done something to the nerve. i have had diarrhea and nausea since doing it...are they linked?

Indirectly: The gi upset could be caused by distress from the injury but shouldn't be a major upset. Severe sprains don't usually damage any nerves but can tear a ligament especially if there was associated ankle swelling and black and blue discoloration. See an orthopedic surgeon if there is persistent pain and swelling beyond the usual 7-10 days. Meanwhile rest,elevate and ice the ankle to reduce swelling.