Hi? My toe turned black?

Hi! I'm here to ask for help about my toe turning black - OK I was at Judo and it started to hurt. I don't know what happened, but one of my toes started to bleed. I took care of it. The other one also hurt, but there were no visual signs something bad had happened. Then my toe turned purple after about a two hour walk. I was helping my mum with the shopping and I complained. She told me to be quiet and when I got home and took off my shoes and socks it was purple. I just got up from dinner and I looked down at my toe, and it's black?