Please explain what happened
I'm riding home from class. I got onto the on ramp to get onto interstate. I'm in the right lane and everyone is doing about 30 so I pull into the left and speed up to the posted 50. I get to the end of the on ramp were the merger is and I go to slip into a decent size hole between an Impala and a suburban. As I'm moving in I hear a siren and instinctivly slow and pull to the break down. The siren then stops. The Impala then rolls past me with the widow down and a guy pointing at me mouthing out "You!". At this point I figure its an unmarked cop so I stop and wait for him to stop but he keeps on going. So I get back onto the road and keep going. As I get onto the interstate I see the cop moving along the road, and unfortunatly, I end up behind him. I'm stuck behind him for a ways until the next exit were anouther lane is added and I get into it and just keep going. The traffic is pretty heavy so we aren't going far. I keep going for a ways and he keeps moving around to stay in sight of me. My lane ends up moving faster than his and as I am moving past him he hits the siren again then turns it off. I just kept going. He kept following me for a while so I slowed down and let him pass, then he would slow down so I didn't get far behind. At this point I;m doing 10 under the speed limit with him one lane over from me. He keeps this up for anouther 15 miles, as cars are passing me doing 85 and 90, and then finally speeds up and moves on. (I did my best to stay out of his sight). But what the hell was going on?!?! Was he just mad because I tried to merge into his lane? WTF! I'm having bad luck with cops lately.