Gertrude,
What you experianced was a reverse squeeze. This is a very common problem in people diving when they have a cold, in your case your reverse squeeze was actually the reverse of the diving condition if you understand me!
When you dive the water pressure doubles for every 10m that you descend. When you have a cold your eustation tubes are blocked usually for some days after the symptons of the cold have gone.
When you ascended the gas in your tubes expanded out of the tubes and mucus then blocked the tubes, as you descended again the airspaces were unable to equalise and you experianced the squeeze on your ears. A carefull valsalva manouver would probably have helped flex the tubes enough to allow the gas to pass back. As you neared the surface the pressure is less prone to change hence the reason that your condition did not feel any worse.
15 years of training technical diving Instructors and I have seen a few squeezes, the great ones look like a scene from aliens!!!