There are so many "against-all-odds" scenarios that would ALL have to take place for you to have been infected on your walk home.
1. A stray needle would have to have been on the sidewalk where you were walking. Not very likely, but possible, sure.
2. That needle would have to have been used by an HIV positive person. And that person would have to have used that needle less than a few hours prior to you stepping on it. HIV is very fragile, it dies pretty quickly upon hitting the air. Most of the time it dies in minutes, but if the environment is right it "can" live on a surface for an hour or three.
3. So let's say, despite RIDICULOUSLY low odds the first two things I mentioned actually happened... You'd still have to have the virus enter your bloodstream. You said the cut was on your toe, a virus entering your bloodstream through a tiny cut on your toe just isn't going to happen.
You have to let this fear go, I know and understand the whole "what if this and what if that" type of thinking we do as hypochondriacs but this fear is completely irrational, I'm sorry that it's lasted this long.
You weren't infected, it's really as simple as that. I don't think you need to get tested and I really don't think you should. Take the next 20 minutes after you read this to keep thinking about what I just told you, and understand all the reasons you weren't infected. When that 20 minutes is up, don't give this fear another second of your life. A year is long enough. Move on.
Best wishes- AP