AIO - A guy driving slowly behind me and in front of me while walking my dog.

So today I (18F) was walking my dog and at first I was on the road. I heard a car coming, looked behind me, determined it was far enough away and crossed the road and went onto the sidewalk (the sidewalk where I would have walked instead of on the road was blocked with a vehicle). Well, that car disappears, and as I'm walking on the sidewalk, I hear a car slowly driving so I look behind me to see why. It's a truck now. No one is crossing the road, no one is in a car in front of them turning, no one is pulling out of a driveway, etc. I keep walking. This person is still going 5 mph (the speed limit is 25 mph). Now the sidewalk ends and I have to start walking on the road again. The truck speeds up to pass me (??). I see the back of a head of a middle-aged, white man driving. Well, the truck looks like it's going to turn onto a street but doesn't turn it's turn signal on and serves to keep going straight. The road he would have turned down had a bunch of guys repaving a sidewalk. Well, he keeps driving at around 5 mph but in the middle of the road and stops every so often. I keep walking but really slow because I don't know what he's doing or what his intentions are. Well, I think (I could just be overreacting and assuming this) he sees a lady watering her plants and goes to the end of the road but he's still in the middle of the road. My dog starts barking at said lady because she isn't trained too well (we're working on that). I start calling my mum at this point just in case. I'm not paying attention to the truck anymore and it drives off. My mum picks up and I stay on the phone with her until I get into our house.

Am I overreacting by thinking this guy was stalking me? Or am I justified for my feelings?

I also think I've seen the truck before but that's reaching a bit because I feel like it might be a pretty common truck. It was a green Santa Cruz Hyundai. Personally, I also think they're ugly.

I went on a rant (Over text messages) about this to my boyfriend and he didn't really have much too say. I said, "maybe I'm paranoid," and he didn't say anything really. He didn't say "no, it's understandable to feel frightened," or "you might be overreacting a little bit." That's why I'm on here posting this.

Also, if you read all of this, thank you. I'm sorry for this big jumbled mess. Also, I'm sorry for any spelling or grammar errors.