I was at the same point as you when I started a Master's program in May 2009 - including the issue with the runner's kick. Do yourself a BIG favor and buy yourself a pair of Zoomers. Focus on kick drills and you will get better - albeit slowly.

I did an Olympic this past weekend in the Pacific and swam freestyle continuously for the entire 1500 meters - with plenty of fuel in the tank at the end. BTW, I am 60+ so age should not be an issue.