Help merging onto highway?

Okay so today I was merging onto the highway. Note that my usually merge lane, we have no yield sign for us merging on, traffic was light. So merging on, I always accelerate to the speed that the traffic on the highway moves and use a blinker. I checked and saw someone in the left lane but they weren't right beside me or in my blindspot. While I was merging over, they decided to haul *** last minute and blaring their horn. Note they were an ambulance and no they had no flashing lights, nada, just driving like normal till this happened. They moved to the empty lane next to them then sped up, the young man proceeded to flip me off! I was like what??? Then they cut me off sharply that I had to press on my brakes. I moved away from them because I was a bit freaked out only to have them speed up to drive up to my window making gestures, I'm not kidding it was seriously weird then they followed me for a distance but exited the highway just to turn around. Should I have called the highway patrol about this behavior or what?