How can i tell my ankle is sprained?

two days ago i was at elephant bar. as i was leaving i missed a big step and i almost fell. my right ankle went inward and i felt some pain but i was shocked about the situation because it was sudden. i didnt feel any pain on my ankle yesterday but when i woke up this morning it hurts when i stand and walk. it hurts startin from the ankle and a little above it. when i touch it, it feels bruised. i dont know if this is a sprain or not. should i wait it out or go to the doctors?