Transmission issues..
 

I tried looking up on here and Google but could only find people having their transmission slipping. Looked up the term and that's not what mine is doing. Hopefully someone here can help.

I drove to work today, everything seemed normal with the car. Driving home, everything seemed a'okay, but when I got on the highway my transmission started acting up. I got up to around 65 and my tach was reading a little about 2k. That's with my foot on the gas holding at a steady speed. When I took my foot off the gas, the tach was still holding about 2k slowing down at a slow rate of speed. The engine itself sounded like it was at a high rev.

When my car dropped down to around 55 (I wasn't pressing the break, just letting it come down on it's own), the tach dropped to around 1,250, I felt the car shift, it went back up to 1,750 and then started to decelerate quickly. The car seemed normal at speeds less than 55.

Also note that when I was approaching a stop light, the car seemed harder to stop. Usually when I am coming to a stop, the engine goes back to a normal idle speed. When I was trying to stop coming home, it was staying around the 1k mark.

The car almost has 72k miles on it. Should I just take it in for a transmission fluid flush? Is there anything I can check for to give you guys more information?

Any help would be great.