I had a tooth out and blood clot fell out after 4 days?

I had my tooth out on Wednesday i had a little pain but mainly due to swelling in my cheek and jaw but by friday it was a lot better no pain from the site at all then on Saturday night i was gargling with salt water (like i had done after food and before bed everyday since extraction) and the blood clot fell out is this normal to fall out? or has it just healed quick? there looks like a hole in the site today is day 5 am i at risk of dry socket? i don't have any pain as such but it does feel different since the colt fell out . Any advice would be great thanks