What does it mean. I'm pretty worried.

Since we don't know your sexual and medical history, we aren't medical doctors, plus we can't examine you (no, please don't post pictures), it's a bit hard to tell what this could be. That means it's time to go to a real-life doctor and find out what this is.

Even lice look like 'spots' that are sort of light brown!

It means you need to go to doctor and have it checked.