How Is HIV Transmitted?

So I was headed to the Bathroom and just when I was about to open the door, I noticed what looked like blood. It was red and shiny and didn t look like it had been there long (as it looked like it had not dried yet). I automatically moved my coat up to cover my hand. I then placed my hand to the left of the spot. However, I do not know if that was the only spot on the door. My coat is black, so I can t tell if any blood got on my coat. Can I continue to wear my coat? Is it ok to place it in my hamper and not worry about any possible blood touching my other clothes? What is my risk of HIV infection? Should I be worried? please help